Changeset 4ed2d0a1 in sasview for src


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Apr 17, 2014 12:38:48 PM (11 years ago)
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  • src/sans/models/media/model_functions.rst

    rd4117ccb r4ed2d0a1  
    210210------------------------------- 
    211211 
    212 - AbsolutePower_Law 
     212- AbsolutePower_Law_ 
    213213- BEPolyelectrolyte 
    214214- BroadPeakModel 
     
    16781678 
    16791679W-R Chen, P. D. Butler and L. J. Magid, *Incorporating Intermicellar Interactions in the Fitting of SANS Data from* 
    1680 *Cationic Wormlike Micelles*. *Langmuir*, 22(15) 2006 6539–6548 
     1680*Cationic Wormlike Micelles*. *Langmuir*, 22(15) 2006 6539–6548 
    16811681 
    16821682 
     
    17661766 
    17671767W-R Chen, P. D. Butler and L. J. Magid, *Incorporating Intermicellar Interactions in the Fitting of SANS Data from* 
    1768 *Cationic Wormlike Micelles*. *Langmuir*, 22(15) 2006 6539–6548 
     1768*Cationic Wormlike Micelles*. *Langmuir*, 22(15) 2006 6539–6548 
    17691769 
    17701770 
     
    19391939.. image:: img/image079.GIF 
    19401940 
    1941 The scattering intensity I(q) is 
     1941The scattering intensity *I(q)* is 
    19421942 
    19431943.. image:: img/image081.PNG 
     
    24212421 
    24222422where |delta|\ T = tail length (or *t_length*), |delta|\ H = head thickness (or *h_thickness*), 
    2423 |bigdelta|\ |rho|\ H = SLD(headgroup) - SLD(solvent), and |bigdelta|\ |rho|\ T = SLD(tail) - SLD(headgroup). 
     2423|bigdelta|\ |rho|\ H = SLD(headgroup) - SLD(solvent), and |bigdelta|\ |rho|\ T = SLD(tail) - SLD(solvent). 
    24242424 
    24252425The 2D scattering intensity is calculated in the same way as 1D, where the *q* vector is defined as 
     
    24542454 
    24552455also in J. Phys. Chem. B, 105, (2001) 11081-11088 
     2456 
     2457*2014/04/17 - Description reviewed by S. King and P. Butler.* 
    24562458 
    24572459 
     
    26652667*2.1.34.1. Definition* 
    26662668 
    2667 The scattering intensity I(q) is calculated as 
     2669The scattering intensity *I(q)* is calculated as 
    26682670 
    26692671.. image:: img/image149.JPG 
     
    31203122The following are models used for shape-independent SANS analysis. 
    31213123 
    3122 **2.2.1. Debye** 
    3123  
    3124 The Debye model is a form factor for a linear polymer chain. In 
    3125 addition to the radius of gyration, Rg, a scale factor "scale", and a 
    3126 constant background term are included in the calculation. 
    3127  
    3128  
    3129  
    3130  
    3131  
    3132  
    3133  
    3134 For 2D plot, the wave transfer is defined as . 
    3135  
    3136  
    3137  
    3138 Parameter name 
    3139  
    3140 Units 
    3141  
    3142 Default value 
    3143  
    3144 scale 
    3145  
    3146 None 
    3147  
    3148 1.0 
    3149  
    3150 rg 
    3151  
    3152  
    3153  
    3154 50.0 
    3155  
    3156 background 
    3157  
    3158 |cm^-1| 
    3159  
    3160 0.0 
    3161  
    3162  
     3124.. _Debye: 
     3125 
     3126**2.2.1. Debye (Model)** 
     3127 
     3128The Debye model is a form factor for a linear polymer chain. In addition 
     3129to the radius of gyration, Rg, a scale factor "scale", and a constant 
     3130background term are included in the calculation. 
     3131 
     3132.. image:: img/image172.PNG 
     3133 
     3134For 2D plot, the wave transfer is defined as 
     3135 
     3136.. image:: img/image040.GIF 
     3137 
     3138==============  ========  ============= 
     3139Parameter name  Units     Default value 
     3140 
     3141==============  ========  ============= 
     3142| scale None 1.0  
     3143 
     3144| rg   Ãƒâ€Š    50.0 
     3145 
     3146| background              | cm-1 0.0  
     3147==============  ========  ============= 
     3148 
     3149.. image:: img/image173.JPG 
    31633150 
    31643151*Figure. 1D plot using the default values (w/200 data point).* 
    31653152 
    3166  
    3167  
    3168 REFERENCE 
    3169  
    3170 R. J. Roe, *Methods of X-Ray and Neutron Scattering in Polymer Science*, Oxford University Press, New York (2000). 
    3171  
    3172 *3.2. BroadPeak Model* 
    3173  
    3174 Calculate an empirical functional form for SANS data characterized by 
    3175 a broad scattering peak. Many SANS spectra are characterized by a 
    3176 broad peak even though they are from amorphous soft materials. The 
    3177 d-spacing corresponding to the broad peak is a characteristic distance 
    3178 between the scattering inhomogeneities (such as in lamellar, 
    3179 cylindrical, or spherical morphologies or for bicontinuous 
    3180 structures). 
    3181  
    3182 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    3183  
    3184 The scattering intensity I(q) is calculated by: 
    3185  
    3186  
    3187  
    3188 Here the peak position is related to the d-spacing as Q0 = 2pi/d0. 
    3189 Soft systems that show a SANS peak include copolymers, 
    3190 polyelectrolytes, multiphase systems, layered structures, etc. 
    3191  
    3192  
    3193  
    3194  
    3195  
    3196 For 2D plot, the wave transfer is defined as . 
    3197  
    3198  
    3199  
    3200 Parameter name 
    3201  
    3202 Units 
    3203  
    3204 Default value 
    3205  
    3206 scale_l (= C) 
    3207  
    3208 10 
    3209  
    3210 scale_p (=A) 
    3211  
    3212 1e-05 
    3213  
    3214 length_l (=x) 
    3215  
    3216  
    3217  
    3218 50 
    3219  
    3220 q_peak (= Q0) 
    3221  
    3222 -1 
    3223  
    3224 0.1 
    3225  
    3226 exponent_p (=n) 
    3227  
    3228 2 
    3229  
    3230 exponent_l (=m) 
    3231  
    3232 3 
    3233  
    3234 Background (=B) 
    3235  
    3236 |cm^-1| 
    3237  
    3238 0.1 
    3239  
    3240  
     3153REFERENCE 
     3154 
     3155Roe, R.-J., "Methods of X-Ray and Neutron Scattering in 
     3156Polymer Science", Oxford University Press, New York (2000). 
     3157 
     3158 
     3159 
     3160.. _BroadPeakModel: 
     3161 
     3162**2.2.2. BroadPeak Model** 
     3163 
     3164Calculate an empirical functional form for SANS data characterized by a 
     3165broad scattering peak. Many SANS spectra are characterized by a broad 
     3166peak even though they are from amorphous soft materials. The d-spacing 
     3167corresponding to the broad peak is a characteristic distance between the 
     3168scattering inhomogeneities (such as in lamellar, cylindrical, or 
     3169spherical morphologies or for bicontinuous structures). 
     3170 
     3171The returned value is scaled to units of |cm^-1|, absolute scale. 
     3172 
     3173The scattering intensity *I(q)* is calculated by:  
     3174 
     3175.. image:: img/image174.JPG 
     3176 
     3177Here the peak position is related to the d-spacing as Q0 = 2pi/d0. Soft 
     3178systems that show a SANS peak include copolymers, polyelectrolytes, 
     3179multiphase systems, layered structures, etc. 
     3180 
     3181For 2D plot, the wave transfer is defined as 
     3182 
     3183.. image:: img/image040.GIF 
     3184 
     3185==============  ========  ============= 
     3186Parameter name  Units     Default value 
     3187==============  ========  ============= 
     3188| scale\_l (= C)          |      10   
     3189 
     3190| scale\_p (=A)           |      1e-05 
     3191 
     3192| length\_l (=x)          | Ã     50   
     3193 
     3194| q\_peak (= Q0)          | Ã -1  0.1  
     3195 
     3196| exponent\_p (=n)        |      2    
     3197 
     3198| exponent\_l (=m)        |      3    
     3199 
     3200| Background (=B)         | cm-1 0.1  
     3201==============  ========  ============= 
     3202 
     3203.. image:: img/image175.JPG 
    32413204 
    32423205*Figure. 1D plot using the default values (w/200 data point).* 
    32433206 
    3244  
    3245  
    3246 REFERENCE 
    3247  
    3248 *None* 
    3249  
    3250 2013/09/09 - Description reviewed by King, S. and Parker, P. 
    3251  
    3252 *3.3. CorrLength (CorrelationLengthModel)* 
    3253  
    3254 Calculate an empirical functional form for SANS data characterized by 
    3255 a low-Q signal and a high-Q signal 
    3256  
    3257 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    3258  
    3259 The scattering intensity I(q) is calculated by: 
    3260  
    3261  
     3207REFERENCE 
     3208 
     3209None. 
     3210 
     3211*2013/09/09 - Description reviewed by King, S. and Parker, P.* 
     3212 
     3213 
     3214 
     3215.. _CorrLength: 
     3216 
     3217**2.2.3. CorrLength (CorrelationLengthModel)** 
     3218 
     3219Calculate an empirical functional form for SANS data characterized by a 
     3220low-Q signal and a high-Q signal 
     3221 
     3222The returned value is scaled to units of |cm^-1|, absolute scale. 
     3223 
     3224The scattering intensity *I(q)* is calculated by:  
     3225 
     3226.. image:: img/image176.JPG 
    32623227 
    32633228The first term describes Porod scattering from clusters (exponent = n) 
    3264 and the second term is a Lorentzian function describing scattering 
    3265 from polymer chains (exponent = m). This second term characterizes the 
     3229and the second term is a Lorentzian function describing scattering from 
     3230polymer chains (exponent = m). This second term characterizes the 
    32663231polymer/solvent interactions and therefore the thermodynamics. The two 
    3267 multiplicative factors A and C, the incoherent background B and the 
    3268 two exponents n and m are used as fitting parameters. The final 
    3269 parameter (xi) is a correlation length for the polymer chains. Note 
    3270 that when m = 2, this functional form becomes the familiar Lorentzian 
    3271 function. 
    3272  
    3273  
    3274  
    3275 For 2D plot, the wave transfer is defined as . 
    3276  
    3277  
    3278  
    3279 Parameter name 
    3280  
    3281 Units 
    3282  
    3283 Default value 
    3284  
    3285 scale_l (= C) 
    3286  
    3287 10 
    3288  
    3289 scale_p (=A) 
    3290  
    3291 1e-06 
    3292  
    3293 length_l (=x) 
    3294  
    3295  
    3296  
    3297 50 
    3298  
    3299 exponent_p (=n) 
    3300  
    3301 2 
    3302  
    3303 exponent_l (=m) 
    3304  
    3305 3 
    3306  
    3307 Background (=B) 
    3308  
    3309 |cm^-1| 
    3310  
    3311 0.1 
    3312  
    3313  
     3232multiplicative factors A and C, the incoherent background B and the two 
     3233exponents n and m are used as fitting parameters. The final parameter 
     3234(xi) is a correlation length for the polymer chains. Note that when m = 
     32352, this functional form becomes the familiar Lorentzian function.  
     3236 
     3237For 2D plot, the wave transfer is defined as 
     3238 
     3239.. image:: img/image040.GIF 
     3240 
     3241==============  ========  ============= 
     3242Parameter name  Units     Default value 
     3243==============  ========  ============= 
     3244| scale\_l (= C)          |      10   
     3245 
     3246| scale\_p (=A)           |      1e-06 
     3247 
     3248| length\_l (=x)          | Ã     50   
     3249 
     3250| exponent\_p (=n)        |      2    
     3251 
     3252| exponent\_l (=m)        |      3    
     3253 
     3254| Background (=B)         | cm-1 0.1  
     3255==============  ========  ============= 
     3256 
     3257.. image:: img/image177.JPG 
    33143258 
    33153259*Figure. 1D plot using the default values (w/500 data points).* 
    33163260 
    3317  
    3318  
    3319 REFERENCE 
    3320  
    3321 B. Hammouda, D.L. Ho and S.R. Kline, *Insight into Clustering in Poly(ethylene oxide) Solutions*, 
    3322 *Macromolecules*, 37 (2004) 6932-6937 
    3323  
    3324 2013/09/09 - Description reviewed by King, S. and Parker, P. 
    3325  
    3326 *3.4. (Ornstein-Zernicke) Lorentz (Model)* 
     3261REFERENCE 
     3262 
     3263B. Hammouda, D.L. Ho and S.R. Kline, Insight into Clustering in 
     3264Poly(ethylene oxide) Solutions, Macromolecules 37, 6932-6937 (2004). 
     3265 
     3266*2013/09/09 - Description reviewed by King, S. and Parker, P.* 
     3267 
     3268 
     3269 
     3270.. _Lorentz: 
     3271 
     3272**2.2.4. (Ornstein-Zernicke) Lorentz (Model)** 
    33273273 
    33283274The Ornstein-Zernicke model is defined by: 
    33293275 
    3330  
    3331  
    3332  
    3333  
    3334  
     3276.. image:: img/image178.PNG 
    33353277 
    33363278The parameter L is referred to as the screening length. 
    33373279 
    3338  
    3339  
    3340 For 2D plot, the wave transfer is defined as . 
    3341  
    3342  
    3343  
    3344  
    3345  
    3346 Parameter name 
    3347  
    3348 Units 
    3349  
    3350 Default value 
    3351  
    3352 scale 
    3353  
    3354 None 
    3355  
    3356 1.0 
    3357  
    3358 length 
    3359  
    3360  
    3361  
    3362 50.0 
    3363  
    3364 background 
    3365  
    3366 |cm^-1| 
    3367  
    3368 0.0 
    3369  
    3370 * * 
     3280For 2D plot, the wave transfer is defined as 
     3281 
     3282.. image:: img/image040.GIF 
     3283 
     3284==============  ========  ============= 
     3285Parameter name  Units     Default value 
     3286==============  ========  ============= 
     3287| scale None 1.0  
     3288 
     3289| length Ã     50.0 
     3290 
     3291| background              | cm-1 0.0  
     3292==============  ========  ============= 
     3293 
     3294.. image:: img/image179.JPG 
     3295 
     3296** Figure. 1D plot using the default values (w/200 data point).** 
     3297 
     3298 
     3299 
     3300.. _DABModel: 
     3301 
     3302**2.2.5. DAB (Debye-Anderson-Brumberger) Model** 
     3303 
     3304Calculates the scattering from a randomly distributed, two-phase system 
     3305based on the Debye-Anderson-Brumberger (DAB) model for such systems. The 
     3306two-phase system is characterized by a single length scale, the 
     3307correlation length, which is a measure of the average spacing between 
     3308regions of phase 1 and phase 2. The model also assumes smooth interfaces 
     3309between the phases and hence exhibits Porod behavior (I ~ Q-4) at large 
     3310Q (Q\*correlation length >> 1). 
     3311 
     3312.. image:: img/image180.PNG 
     3313 
     3314The parameter L is referred to as the correlation length. 
     3315 
     3316For 2D plot, the wave transfer is defined as 
     3317 
     3318.. image:: img/image040.GIF 
     3319 
     3320==============  ========  ============= 
     3321Parameter name  Units     Default value 
     3322==============  ========  ============= 
     3323| scale None 1.0  
     3324 
     3325| length Ã     50.0 
     3326 
     3327| background              | cm-1 0.0  
     3328==============  ========  ============= 
     3329 
     3330.. image:: img/image181.JPG 
     3331 
     3332** Figure. 1D plot using the default values (w/200 data point).** 
     3333 
     3334REFERENCE 
     3335 
     3336Debye, Anderson, Brumberger, "Scattering by an Inhomogeneous Solid. II. 
     3337The Correlation Function and its Application", J. Appl. Phys. 28 (6), 
     3338679 (1957). 
     3339 
     3340Debye, Bueche, "Scattering by an Inhomogeneous Solid", J. Appl. Phys. 
     334120, 518 (1949). 
     3342 
     3343*2013/09/09 - Description reviewed by King, S. and Parker, P.* 
     3344 
     3345 
     3346 
     3347.. _AbsolutePower_Law: 
     3348 
     3349**2.2.6.  Absolute Power\_Law** 
     3350 
     3351This model describes a power law with background. 
     3352 
     3353.. image:: img/image182.PNG 
     3354 
     3355Note the minus sign in front of the exponent. 
     3356 
     3357==============  ========  ============= 
     3358Parameter name  Units     Default value 
     3359==============  ========  ============= 
     3360| Scale None 1.0  
     3361 
     3362| m    None 4    
     3363 
     3364| Background              | cm-1 0.0  
     3365==============  ========  ============= 
     3366 
     3367.. image:: img/image183.JPG 
    33713368 
    33723369*Figure. 1D plot using the default values (w/200 data point).* 
    33733370 
    3374 *3.5. DAB (Debye-Anderson-Brumberger)_Model* 
    3375  
    3376  
    3377  
    3378 Calculates the scattering from a randomly distributed, two-phase 
    3379 system based on the Debye-Anderson-Brumberger (DAB) model for such 
    3380 systems. The two-phase system is characterized by a single length 
    3381 scale, the correlation length, which is a measure of the average 
    3382 spacing between regions of phase 1 and phase 2. The model also assumes 
    3383 smooth interfaces between the phases and hence exhibits Porod behavior 
    3384 (I ~ Q-4) at large Q (Q*correlation length >> 1). 
    3385  
    3386  
    3387  
    3388  
    3389  
    3390  
    3391  
    3392 The parameter L is referred to as the correlation length. 
    3393  
    3394 For 2D plot, the wave transfer is defined as . 
    3395  
    3396  
    3397  
    3398 Parameter name 
    3399  
    3400 Units 
    3401  
    3402 Default value 
    3403  
    3404 scale 
    3405  
    3406 None 
    3407  
    3408 1.0 
    3409  
    3410 length 
    3411  
    3412  
    3413  
    3414 50.0 
    3415  
    3416 background 
    3417  
    3418 |cm^-1| 
    3419  
    3420 0.0 
    3421  
    3422 * * 
    3423  
    3424 *Figure. 1D plot using the default values (w/200 data point).* 
    3425  
    3426 REFERENCE 
    3427  
    3428 Debye, Bueche, *Scattering by an Inhomogeneous Solid*, *J. Appl. Phys.*, 20 (1949) 518 
    3429  
    3430 Debye, Anderson, Brumberger, *Scattering by an Inhomogeneous Solid. II. The Correlation Function and its Application*, 
    3431 *J. Appl. Phys.*, 28(6), (1957) 679 
    3432  
    3433 2013/09/09 - Description reviewed by King, S. and Parker, P. 
    3434  
    3435  
    3436  
    3437 **3.6. AbsolutePowerLaw** 
    3438  
    3439 This model describes a power law with background. 
    3440  
    3441  
    3442  
    3443  
    3444  
    3445 Note the minus sign in front of the exponent. 
    3446  
    3447  
    3448  
    3449 Parameter name 
    3450  
    3451 Units 
    3452  
    3453 Default value 
    3454  
    3455 Scale 
    3456  
    3457 None 
    3458  
    3459 1.0 
    3460  
    3461 m 
    3462  
    3463 None 
    3464  
    3465 4 
    3466  
    3467 Background 
    3468  
    3469 |cm^-1| 
    3470  
    3471 0.0 
    3472  
    3473  
    3474  
    3475 *Figure. 1D plot using the default values (w/200 data point).* 
    3476  
    3477 *3.7. Teubner Strey (Model)* 
     3371 
     3372 
     3373.. _Teubner Strey: 
     3374 
     3375**2.2.7. Teubner Strey (Model)** 
    34783376 
    34793377This function calculates the scattered intensity of a two-component 
    34803378system using the Teubner-Strey model. 
    34813379 
    3482  
    3483  
    3484  
    3485  
    3486  
    3487  
    3488  
    3489  
    3490 For 2D plot, the wave transfer is defined as . 
    3491  
    3492  
    3493  
    3494 Parameter name 
    3495  
    3496 Units 
    3497  
    3498 Default value 
    3499  
    3500 scale 
    3501  
    3502 None 
    3503  
    3504 0.1 
    3505  
    3506 c1 
    3507  
    3508 None 
    3509  
    3510 -30.0 
    3511  
    3512 c2 
    3513  
    3514 None 
    3515  
    3516 5000.0 
    3517  
    3518 background 
    3519  
    3520 |cm^-1| 
    3521  
    3522 0.0 
    3523  
    3524  
     3380.. image:: img/image184.PNG 
     3381 
     3382For 2D plot, the wave transfer is defined as 
     3383 
     3384.. image:: img/image040.GIF 
     3385 
     3386==============  ========  ============= 
     3387Parameter name  Units     Default value 
     3388==============  ========  ============= 
     3389| scale None 0.1  
     3390 
     3391| c1   None -30.0 
     3392 
     3393| c2   None 5000.0 
     3394 
     3395| background              | cm-1 0.0  
     3396==============  ========  ============= 
     3397 
     3398.. image:: img/image185.JPG 
    35253399 
    35263400*Figure. 1D plot using the default values (w/200 data point).* 
     
    35283402REFERENCE 
    35293403 
    3530 Teubner, M; Strey, R. J. Chem. Phys., 87, 3195 (1987) 
    3531  
    3532  
    3533  
    3534 Schubert, K-V., Strey, R., Kline, S. R. and E. W. Kaler, J. Chem. 
    3535 Phys., 101, 5343 (1994). 
    3536  
    3537 *3.8.  FractalModel* 
     3404Teubner, M; Strey, R. J. Chem. Phys., 87, 3195 (1987). 
     3405 
     3406Schubert, K-V., Strey, R., Kline, S. R. and E. W. Kaler, J. Chem. Phys., 
     3407101, 5343 (1994). 
     3408 
     3409 
     3410 
     3411.. _FractalModel: 
     3412 
     3413**2.2.8.  FractalModel** 
    35383414 
    35393415Calculates the scattering from fractal-like aggregates built from 
    35403416spherical building blocks following the Texiera reference. The value 
    3541 returned is in |cm^-1|. 
    3542  
    3543  
    3544  
    3545  
    3546  
    3547  
    3548  
    3549 The scale parameter is the volume fraction of the building blocks, R0 
    3550 is the radius of the building block, Df is the fractal dimension, is 
    3551 the correlation length, *solvent* is the scattering length density of 
    3552 the solvent, and *block* is the scattering length density of the 
    3553 building blocks. 
    3554  
    3555 *The polydispersion in radius is provided.* 
    3556  
    3557 For 2D plot, the wave transfer is defined as . 
    3558  
    3559  
    3560  
    3561 Parameter name 
    3562  
    3563 Units 
    3564  
    3565 Default value 
    3566  
    3567 scale 
    3568  
    3569 None 
    3570  
    3571 0.05 
    3572  
    3573 radius 
    3574  
    3575  
    3576  
    3577 5.0 
    3578  
    3579 fractal_dim 
    3580  
    3581 None 
    3582  
    3583 2 
    3584  
    3585 corr_length 
    3586  
    3587  
    3588  
    3589 100.0 
    3590  
    3591 block_sld 
    3592  
    3593 -2 
    3594  
    3595 2e-6 
    3596  
    3597 solvent_sld 
    3598  
    3599 -2 
    3600  
    3601 6e-6 
    3602  
    3603 background 
    3604  
    3605 |cm^-1| 
    3606  
    3607 0.0 
    3608  
    3609  
     3417returned is in cm-1. 
     3418 
     3419.. image:: img/image186.PNG 
     3420 
     3421The scale parameter is the volume fraction of the building blocks, R0 is 
     3422the radius of the building block, Df is the fractal dimension, Ο is the 
     3423correlation length, *Ïᅵsolvent* is the scattering length density of the 
     3424solvent, and *Ïᅵblock* is the scattering length density of the building 
     3425blocks. 
     3426 
     3427**The polydispersion in radius is provided.** 
     3428 
     3429For 2D plot, the wave transfer is defined as 
     3430 
     3431.. image:: img/image040.GIF 
     3432 
     3433==============  ========  ============= 
     3434Parameter name  Units     Default value 
     3435==============  ========  ============= 
     3436| scale None 0.05 
     3437 
     3438| radius Ã     5.0  
     3439 
     3440| fractal\_dim            | None 2    
     3441 
     3442| corr\_length            | Ã     100.0 
     3443 
     3444| block\_sld              | Ã -2  2e-6 
     3445 
     3446| solvent\_sld            | Ã -2  6e-6 
     3447 
     3448| background              | cm-1 0.0  
     3449==============  ========  ============= 
     3450 
     3451.. image:: img/image187.JPG 
    36103452 
    36113453*Figure. 1D plot using the default values (w/200 data point).* 
    36123454 
    3613  
    3614  
    3615  
    3616  
    36173455REFERENCE 
    36183456 
     
    36213459 
    36223460 
    3623 *3.9. MassFractalModel* 
     3461.. _MassFractalModel: 
     3462 
     3463**2.2.9. MassFractalModel** 
    36243464 
    36253465Calculates the scattering from fractal-like aggregates based on the 
    3626 Mildner reference (below). 
    3627  
    3628  
    3629  
    3630  
    3631  
    3632  
    3633  
    3634  
    3635  
     3466Mildner reference (below).  
     3467 
     3468.. image:: img/mass_fractal_eq1.JPG 
    36363469 
    36373470The R is the radius of the building block, Dm is the mass fractal 
    3638 dimension, is the correlation (or cutt-off) length, *solvent* is the 
    3639 scattering length density of the solvent, and *particle* is the 
     3471dimension, Ο is the correlation (or cutt-off)  length, *Ïᅵsolvent* is the 
     3472scattering length density of the solvent, and *Ïᅵparticle* is the 
    36403473scattering length density of particles. 
    36413474 
    3642 NB: The mass fractal dimension is valid for 1<mass_dim<6. 
    3643  
    3644  
    3645  
    3646 Parameter name 
    3647  
    3648 Units 
    3649  
    3650 Default value 
    3651  
    3652 scale 
    3653  
    3654 None 
    3655  
    3656 1 
    3657  
    3658 radius 
    3659  
    3660  
    3661  
    3662 10.0 
    3663  
    3664 mass_dim 
    3665  
    3666 None 
    3667  
    3668 1.9 
    3669  
    3670 co_length 
    3671  
    3672  
    3673  
    3674 100.0 
    3675  
    3676 background 
    3677  
    3678  
    3679  
    3680 0.0 
    3681  
    3682  
     3475Note:  The mass fractal dimension is valid for 1<mass\_dim<6. 
     3476 
     3477==============  ========  ============= 
     3478Parameter name  Units     Default value 
     3479==============  ========  ============= 
     3480| scale None 1    
     3481 
     3482| radius Ã     10.0 
     3483 
     3484| mass\_dim               | None 1.9  
     3485 
     3486| co\_length              | Ã     100.0 
     3487 
     3488| background              |      0.0  
     3489==============  ========  ============= 
     3490 
     3491.. image:: img/mass_fractal_fig1.JPG 
    36833492 
    36843493*Figure. 1D plot* 
    36853494 
    3686  
    3687  
    3688  
    3689  
    3690 REFERENCE 
    3691  
    3692 D. Mildner, and P. Hall, J. Phys. D.: Appl. Phys., 19, 1535-1545 
     3495REFERENCE 
     3496 
     3497D. Mildner, and P. Hall,  J. Phys. D.: Appl. Phys.,  19, 1535-1545  
    36933498(1986), Equation(9). 
    36943499 
    3695 2013/09/09 - Description reviewed by King, S. and Parker, P. 
    3696  
    3697  
    3698  
    3699  
    3700  
    3701 *3.10.  SurfaceFractalModel* 
    3702  
    3703 Calculates the scattering based on the Mildner reference (below). 
    3704  
    3705  
    3706  
    3707  
    3708  
    3709  
    3710  
    3711  
    3712  
     3500*2013/09/09 - Description reviewed by King, S. and Parker, P.* 
     3501 
     3502 
     3503 
     3504.. _SurfaceFractalModel: 
     3505 
     3506**2.2.10. SurfaceFractalModel** 
     3507 
     3508Calculates the scattering  based on the Mildner reference (below).  
     3509 
     3510.. image:: img/surface_fractal_eq1.GIF  
    37133511 
    37143512The R is the radius of the building block, Ds is the surface fractal 
    3715 dimension, is the correlation (or cutt-off) length, *solvent* is the 
    3716 scattering length density of the solvent, and *particle* is the 
     3513dimension, Ο is the correlation (or cutt-off)  length, *Ïᅵsolvent* is the 
     3514scattering length density of the solvent, and *Ïᅵparticle* is the 
    37173515scattering length density of particles. 
    37183516 
    3719 NB: The surface fractal dimension is valid for 1<surface_dim<3. Also 
    3720 it is valid in a limited q range (see the reference for details). 
    3721  
    3722  
    3723  
    3724 Parameter name 
    3725  
    3726 Units 
    3727  
    3728 Default value 
    3729  
    3730 scale 
    3731  
    3732 None 
    3733  
    3734 1 
    3735  
    3736 radius 
    3737  
    3738  
    3739  
    3740 10.0 
    3741  
    3742 surface_dim 
    3743  
    3744 None 
    3745  
    3746 2.0 
    3747  
    3748 co_length 
    3749  
    3750  
    3751  
    3752 500.0 
    3753  
    3754 background 
    3755  
    3756  
    3757  
    3758 0.0 
    3759  
    3760  
     3517 Note:  The surface fractal dimension is valid for 1<surface\_dim<3. 
     3518 Also it is valid in a limited q range (see the reference for details). 
     3519 
     3520==============  ========  ============= 
     3521Parameter name  Units     Default value 
     3522==============  ========  ============= 
     3523| scale None 1    
     3524 
     3525| radius Ã     10.0 
     3526 
     3527| surface\_dim            | None 2.0  
     3528 
     3529| co\_length              | Ã     500.0 
     3530 
     3531| background              |      0.0  
     3532==============  ========  ============= 
     3533 
     3534.. image:: img/surface_fractal_fig1.JPG 
    37613535 
    37623536*Figure. 1D plot* 
    37633537 
    3764  
    3765  
    3766  
    3767  
    3768 REFERENCE 
    3769  
    3770 D. Mildner, and P. Hall, J. Phys. D.: Appl. Phys., 19, 1535-1545 
     3538REFERENCE 
     3539 
     3540D. Mildner, and P. Hall,  J. Phys. D.: Appl. Phys.,  19, 1535-1545  
    37713541(1986), Equation(13). 
    37723542 
    37733543 
    37743544 
    3775  
    3776  
    3777 *3.11. MassSurfaceFractal* 
     3545.. _MassSurfaceFractal: 
     3546 
     3547**2.2.11. MassSurfaceFractal** 
    37783548 
    37793549A number of natural and commercial processes form high-surface area 
     
    37823552fume or pyrogenic silicas. These are all characterised by cluster mass 
    37833553distributions (sometimes also cluster size distributions) and internal 
    3784 surfaces that are fractal in nature. The scattering from such 
     3554surfaces that are fractal in nature.   The scattering from such 
    37853555materials displays two distinct breaks in log-log representation, 
    37863556corresponding to the radius-of-gyration of the primary particles, rg, 
    37873557and the radius-of-gyration of the clusters (aggregates), Rg. Between 
    3788 these boundaries the scattering follows a power law related to the 
    3789 mass fractal dimension, Dm, whilst above the high-Q boundary the 
    3790 scattering follows a power law related to the surface fractal 
    3791 dimension of the primary particles, Ds. 
    3792  
    3793 The scattered intensity I(Q) is then calculated using a modified 
     3558these boundaries the scattering follows a power law related to the mass 
     3559fractal dimension, Dm, whilst above the high-Q boundary the scattering 
     3560follows a power law related to the surface fractal dimension of the 
     3561primary particles, Ds. 
     3562 
     3563The scattered intensity *I(q)* is then calculated using a modified 
    37943564Ornstein-Zernicke equation: 
    37953565 
    3796  
    3797  
    3798  
    3799  
    3800  
    3801  
    3802  
    3803  
     3566.. image:: img/masssurface_fractal_eq1.JPG  
    38043567 
    38053568The Rg is for the cluster, rg is for the primary, Ds is the surface 
    3806 fractal dimension, Dm is the mass fractal dimension, *solvent* is the 
    3807 scattering length density of the solvent, and *p* is the scattering 
     3569fractal dimension, Dm is the mass fractal dimension, *Ïᅵsolvent* is the 
     3570scattering length density of the solvent, and *Ïᅵp* is the scattering 
    38083571length density of particles. 
    38093572 
    3810 NB: The surface and mass fractal dimensions are valid for 
    3811 0<surface_dim<6, 0<mass_dim<6, and (surface_mass+mass_dim)<6. 
    3812  
    3813  
    3814  
    3815 Parameter name 
    3816  
    3817 Units 
    3818  
    3819 Default value 
    3820  
    3821 scale 
    3822  
    3823 None 
    3824  
    3825 1 
    3826  
    3827 primary_rg 
    3828  
    3829  
    3830  
    3831 4000.0 
    3832 cluster_rg 86.7 
    3833 surface_dim 
    3834  
    3835 None 
    3836  
    3837 2.3 
    3838 mass_dim None 1.8 
    3839 background 
    3840  
    3841  
    3842  
    3843 0.0 
    3844  
    3845  
     3573 Note:  The surface and mass fractal dimensions are valid for 
     35740<surface\_dim<6, 0<mass\_dim<6, and (surface\_mass+mass\_dim)<6.  
     3575 
     3576==============  ========  ============= 
     3577Parameter name  Units     Default value 
     3578==============  ========  ============= 
     3579| scale None 1    
     3580 
     3581| primary\_rg             | Ã     4000.0 
     3582 
     3583|   cluster\_rg           |   Ã    86.7 
     3584 
     3585| surface\_dim            | None 2.3  
     3586 
     3587|   mass\_dim             |  None  1.8 
     3588 
     3589| background              |      0.0  
     3590==============  ========  ============= 
     3591 
     3592.. image:: img/masssurface_fractal_fig1.JPG 
    38463593 
    38473594*Figure. 1D plot* 
    38483595 
    3849  
    3850  
    3851  
    3852  
    3853 REFERENCE 
    3854  
    3855 P. Schmidt, J Appl. Cryst., 24, 414-435 (1991), Equation(19). 
    3856  
    3857 Hurd, Schaefer, Martin, Phys. Rev. A, 35, 2361-2364 (1987), 
    3858 Equation(2). 
    3859  
    3860  
    3861  
    3862  
    3863  
    3864 *3.12.  FractalCoreShell(Model)* 
     3596REFERENCE 
     3597 
     3598P. Schmidt, J Appl. Cryst., 24, 414-435  (1991), Equation(19). 
     3599 
     3600Hurd, Schaefer, Martin, Phys. Rev. A, 35, 2361-2364 (1987), Equation(2). 
     3601 
     3602 
     3603 
     3604.. _FractalCoreShell: 
     3605 
     3606**2.2.12.  FractalCoreShell(Model)** 
    38653607 
    38663608Calculates the scattering from a fractal structure with a primary 
    38673609building block of core-shell spheres. 
    38683610 
    3869  
    3870  
    3871  
    3872 The formfactor P(q) is CoreShellModel with bkg = 0, 
    3873 , 
     3611.. image:: img/fractcore_eq1.GIF 
     3612 
     3613The formfactor P(q) is `CoreShellModel <#CoreShellModel>`__ with bkg 
     3614= 0, 
     3615 
     3616.. image:: img/image013.PNG 
    38743617 
    38753618while the fractal structure factor S(q); 
    38763619 
    3877  
    3878  
    3879 where Df = frac_dim, = cor_length, rc = (core) radius, and scale = 
    3880 volfraction. 
    3881 The fractal structure is as documented in the fractal model. This 
    3882 model could find use for aggregates of coated particles, or aggregates 
    3883 of vesicles.The polydispersity computation of radius and thickness is 
     3620.. image:: img/fractcore_eq3.gif 
     3621 
     3622where Df = frac\_dim, Ο = cor\_length, rc = (core) radius, and scale 
     3623= volfraction. 
     3624 
     3625The fractal structure is as documented in the fractal model. This model 
     3626could find use for aggregates of coated particles, or aggregates of 
     3627vesicles. The polydispersity computation of radius and thickness is 
    38843628provided. 
    38853629 
    3886 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    3887  
    3888 See each of these individual models for full documentation. 
    3889  
    3890 For 2D plot, the wave transfer is defined as . 
    3891  
    3892  
    3893  
    3894 Parameter name 
    3895  
    3896 Units 
    3897  
    3898 Default value 
    3899  
    3900 volfraction 
    3901  
    3902 0.05 
    3903  
    3904 frac_dim 
    3905  
    3906 2 
    3907  
    3908 thickness 
    3909  
    3910  
    3911  
    3912 5.0 
    3913  
    3914 raidus 
    3915  
    3916 20.0 
    3917  
    3918 cor_length 
    3919  
    3920  
    3921  
    3922 100.0 
    3923  
    3924 core_sld 
    3925  
    3926 -2 
    3927  
    3928 3.5e-6 
    3929  
    3930 shell_sld 
    3931  
    3932 -2 
    3933  
    3934 1e-6 
    3935  
    3936 solvent_sld 
    3937  
    3938 -2 
    3939  
    3940 6.35e-6 
    3941  
    3942 background 
    3943  
    3944 |cm^-1| 
    3945  
    3946 0.0 
    3947  
    3948  
     3630The returned value is scaled to units of |cm^-1|, absolute scale. 
     3631 
     3632See each of these individual models for full documentation.  
     3633 
     3634For 2D plot, the wave transfer is defined as 
     3635 
     3636.. image:: img/image040.GIF 
     3637 
     3638==============  ========  ============= 
     3639Parameter name  Units     Default value 
     3640==============  ========  ============= 
     3641| volfraction             |      0.05 
     3642 
     3643| frac\_dim               |      2    
     3644 
     3645| thickness               | Ã     5.0  
     3646 
     3647| raidus  Ã    20.0 
     3648 
     3649| cor\_length             | Ã     100.0 
     3650 
     3651| core\_sld               | Ã -2  3.5e-6 
     3652 
     3653| shell\_sld              | Ã -2  1e-6 
     3654 
     3655| solvent\_sld            | Ã -2  6.35e-6 
     3656 
     3657| background              | cm-1 0.0  
     3658==============  ========  ============= 
     3659 
     3660.. image:: img/image188.JPG 
    39493661 
    39503662*Figure. 1D plot using the default values (w/500 data points).* 
    39513663 
    3952  
    3953  
    3954  
    3955  
    3956 REFERENCE 
    3957  
    3958 See the PolyCore and Fractal documentation. * * 
    3959  
    3960 *3.13.  GaussLorentzGel(Model)* 
     3664REFERENCE 
     3665 
     3666See the PolyCore and Fractal documentation.\ 
     3667 
     3668 
     3669 
     3670.. _GaussLorentzGel: 
     3671 
     3672**2.2.13.  GaussLorentzGel(Model)** 
    39613673 
    39623674Calculates the scattering from a gel structure, typically a physical 
     
    39653677structures. 
    39663678 
    3967 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    3968  
    3969 The scattering intensity I(q) is calculated as (eqn 5 from the 
     3679The returned value is scaled to units of |cm^-1|, absolute scale. 
     3680 
     3681The scattering intensity *I(q)* is calculated as (eqn 5 from the 
    39703682reference): 
    39713683 
    3972  
    3973  
    3974  
     3684.. image:: img/image189.JPG 
    39753685 
    39763686Uppercase Zeta is the static correlations in the gel, which can be 
    3977 attributed to the "frozen-in" crosslinks of some gels. Lowercase zeta 
    3978 is the dynamic correlation length, which can be attributed to the 
     3687attributed to the "frozen-in" crosslinks of some gels. Lowercase zeta is 
     3688the dynamic correlation length, which can be attributed to the 
    39793689fluctuating polymer chain between crosslinks. IG(0) and IL(0) are the 
    39803690scaling factors for each of these structures. Your physical system may 
    39813691be different, so think about the interpretation of these parameters. 
    39823692 
    3983 Note that the peaked structure at higher q values (from Figure 2 of 
    3984 the reference below) is not reproduced by the model. Peaks can be 
    3985 introduced into the model by summing this model with the PeakGauss 
    3986 Model function. 
    3987  
    3988 For 2D plot, the wave transfer is defined as . 
    3989  
    3990  
    3991  
    3992 Parameter name 
    3993  
    3994 Units 
    3995  
    3996 Default value 
    3997  
    3998 dyn_colength(=Dynamic correlation length) 
    3999  
    4000  
    4001  
    4002 20.0 
    4003  
    4004 scale_g(=Gauss scale factor) 
    4005  
    4006 100 
    4007  
    4008 scale_l(=Lorentzian scale factor) 
    4009  
    4010 50 
    4011  
    4012 stat_colength(=Static correlation Z) 
    4013  
    4014  
    4015  
    4016 100.0 
    4017  
    4018 background 
    4019  
    4020 |cm^-1| 
    4021  
    4022 0.0 
    4023  
    4024  
     3693Note that the peaked structure at higher q values (from Figure 2 of the 
     3694reference below) is not reproduced by the model. Peaks can be introduced 
     3695into the model by summing this model with the PeakGauss Model function. 
     3696 
     3697For 2D plot, the wave transfer is defined as 
     3698 
     3699.. image:: img/image040.GIF 
     3700 
     3701==============  ========  ============= 
     3702Parameter name  Units     Default value 
     3703==============  ========  ============= 
     3704| dyn\_colength(=Dynamic  | Ã     20.0 
     3705| correlation length)     |           
     3706 
     3707| scale\_g(=Gauss scale   |      100  
     3708| factor)           
     3709 
     3710| scale\_l(=Lorentzian    |      50   
     3711| scale factor)           |           
     3712 
     3713| stat\_colength(=Static  | Ã     100.0 
     3714| correlation Z)          |           
     3715 
     3716| background              | cm-1 0.0  
     3717==============  ========  ============= 
     3718 
     3719.. image:: img/image190.JPG 
    40253720 
    40263721*Figure. 1D plot using the default values (w/500 data points).* 
    4027  
    4028  
    4029  
    4030  
    40313722 
    40323723REFERENCE 
     
    40353726(2001) 2907-2913. 
    40363727 
    4037 *3.14.  BEPolyelectrolyte Model* 
     3728 
     3729 
     3730.. _BEPolyelectrolyte: 
     3731 
     3732**2.2.14.  BEPolyelectrolyte Model** 
    40383733 
    40393734Calculates the structure factor of a polyelectrolyte solution with the 
    4040 RPA expression derived by Borue and Erukhimovich. The value returned 
    4041 is in |cm^-1|. 
    4042  
    4043  
    4044  
    4045  
    4046  
    4047  
     3735RPA expression derived by Borue and Erukhimovich. The value returned is 
     3736in cm-1. 
     3737 
     3738.. image:: img/image191.PNG 
    40483739 
    40493740K is a contrast factor of the polymer, Lb is the Bjerrum length, h is 
    40503741the virial parameter, b is the monomer length, Cs is the concentration 
    4051 of monovalent salt, is the ionization degree, Ca is the polymer molar 
     3742of monovalent salt, α is the ionization degree, Ca is the polymer molar 
    40523743concentration, and background is the incoherent background. 
    40533744 
    4054 For 2D plot, the wave transfer is defined as . 
    4055  
    4056 Parameter name 
    4057  
    4058 Units 
    4059  
    4060 Default value 
    4061  
    4062 K 
    4063  
    4064 Barns = 10-24 cm2 
    4065  
    4066 10 
    4067  
    4068 Lb 
    4069  
    4070  
    4071  
    4072 7.1 
    4073  
    4074 h 
    4075  
    4076 -3 
    4077  
    4078 12 
    4079  
    4080 b 
    4081  
    4082  
    4083  
    4084 10 
    4085  
    4086 Cs 
    4087  
    4088 Mol/L 
    4089  
    4090 0 
    4091  
    4092 alpha 
    4093  
    4094 None 
    4095  
    4096 0.05 
    4097  
    4098 Ca 
    4099  
    4100 Mol/L 
    4101  
    4102 0.7 
    4103  
    4104 background 
    4105  
    4106 |cm^-1| 
    4107  
    4108 0.0 
     3745For 2D plot, the wave transfer is defined as 
     3746 
     3747.. image:: img/image040.GIF 
     3748 
     3749==============  ========  ============= 
     3750Parameter name  Units     Default value 
     3751==============  ========  ============= 
     3752| K    Barns = 10-24 cm2       | 10   
     3753 
     3754| Lb   Ãƒâ€Š    7.1  
     3755 
     3756| h    Ã -3  12   
     3757 
     3758| b    Ã     10   
     3759 
     3760| Cs   Mol/L 0    
     3761 
     3762| alpha None 0.05 
     3763 
     3764| Ca   Mol/L 0.7  
     3765 
     3766| background              | cm-1 0.0  
     3767==============  ========  ============= 
    41093768 
    41103769REFERENCE 
     
    41153774 
    41163775Moussaid, A., Schosseler, F., Munch, J.-P., Candau, S. J. Journal de 
    4117 Physique II France, 3, 573 (1993). 
    4118  
    4119 Raphal, E., Joanny, J.-F., Europhysics Letters 11, 179 (1990). 
    4120  
    4121  
    4122  
    4123 *3.15. Guinier (Model)* 
    4124  
    4125 A Guinier analysis is done by linearizing the data at low q by 
    4126 plotting it as log(I) versus Q2. The Guinier radius Rg can be obtained 
    4127 by fitting the following model: 
    4128  
    4129  
    4130  
    4131  
    4132  
    4133 For 2D plot, the wave transfer is defined as . 
    4134  
    4135  
    4136  
    4137 Parameter name 
    4138  
    4139 Units 
    4140  
    4141 Default value 
    4142  
    4143 scale 
    4144  
    4145 |cm^-1| 
    4146  
    4147 1.0 
    4148  
    4149 Rg 
    4150  
    4151  
    4152  
    4153 0.1 
    4154  
    4155  
    4156  
    4157 *3.16. GuinierPorod (Model)* 
     3776Physique II France 3, 573 (1993). 
     3777 
     3778Raphaël, E., Joanny, J.-F., Europhysics Letters 11, 179 (1990). 
     3779 
     3780 
     3781 
     3782.. _Guinier: 
     3783 
     3784**2.2.15. Guinier (Model)** 
     3785 
     3786A Guinier analysis is done by linearizing the data at low q by plotting 
     3787it as log(I) versus Q2. The Guinier radius Rg can be obtained by fitting 
     3788the following model: 
     3789 
     3790.. image:: img/image192.PNG 
     3791 
     3792For 2D plot, the wave transfer is defined as 
     3793 
     3794.. image:: img/image040.GIF 
     3795 
     3796==============  ========  ============= 
     3797Parameter name  Units     Default value 
     3798==============  ========  ============= 
     3799| scale cm-1 1.0  
     3800 
     3801| Rg   Ãƒâ€Š    0.1  
     3802==============  ========  ============= 
     3803 
     3804 
     3805 
     3806.. _GuinierPorod: 
     3807 
     3808**2.2.16. GuinierPorod (Model)** 
    41583809 
    41593810Calculates the scattering for a generalized Guinier/power law object. 
     
    41623813 
    41633814The returned value is P(Q) as written in equation (1), plus the 
    4164 incoherent background term. The result is in the units of |cm^-1|\ |sr^-1|, 
     3815incoherent background term. The result is in the units of |cm^-1|, 
    41653816absolute scale. 
    41663817 
     
    41683819asymmetric objects such as rods or platelets. It also applies to 
    41693820intermediate shapes between spheres and rod or between rods and 
    4170 platelets. The following functional form is used: 
    4171  
    4172 (1) 
    4173  
    4174  
    4175  
    4176 This is based on the generalized Guinier law for such elongated 
    4177 objects [2]. For 3D globular objects (such as spheres), s = 0 and one 
    4178 recovers the standard Guinier formula. For 2D symmetry (such as for 
    4179 rods) s = 1 and for 1D symmetry (such as for lamellae or platelets) s 
    4180 = 2. A dimensionality parameter 3-s is defined, and is 3 for spherical 
    4181 objects, 2 for rods, and 1 for plates. 
     3821platelets. The following functional form is used:  
     3822 
     3823.. image:: img/image193.JPG   (1) 
     3824 
     3825This is based on the generalized Guinier law for such elongated objects 
     3826[2]. For 3D globular objects (such as spheres), s = 0 and one recovers 
     3827the standard Guinier formula. For 2D symmetry (such as for rods) s = 1 
     3828and for 1D symmetry (such as for lamellae or platelets) s = 2. A 
     3829dimensionality parameter 3-s is defined, and is 3 for spherical objects, 
     38302 for rods, and 1 for plates. 
    41823831 
    41833832Enforcing the continuity of the Guinier and Porod functions and their 
    4184 derivatives yields: 
    4185  
    4186  
     3833derivatives yields:  
     3834 
     3835.. image:: img/image194.JPG 
    41873836 
    41883837and 
    41893838 
    4190  
    4191  
    4192  
    4193  
    4194 Note that the radius of gyration for a sphere of radius R is given by 
    4195 Rg = R sqrt(3/5) , 
    4196  
    4197 that for the cross section of an randomly oriented cylinder of radius 
    4198 R is given by Rg = R / sqrt(2). 
    4199  
    4200 The cross section of a randomly oriented lamella of thickness T is 
    4201 given by Rg = T / sqrt(12). 
     3839.. image:: img/image195.JPG 
     3840 
     3841Note that the radius of gyration for a sphere of radius R is given by Rg 
     3842= R sqrt(3/5) , 
     3843 
     3844 that for the cross section of an randomly oriented cylinder of radius R 
     3845is given by  Rg = R / sqrt(2). 
     3846 
     3847The cross section of a randomly oriented lamella of thickness T is given 
     3848by Rg = T / sqrt(12). 
    42023849 
    42033850The intensity given by Eq. 1 is the calculated result, and is plotted 
     
    42103857 
    42113858[2] Glatter, O.; Kratky, O., Small-Angle X-Ray Scattering, Academic 
    4212 Press (1982). Check out Chapter 4 on Data Treatment, pages 155-156. 
    4213  
    4214 For 2D plot, the wave transfer is defined as . 
    4215  
    4216  
    4217  
    4218 Parameter name 
    4219  
    4220 Units 
    4221  
    4222 Default value 
    4223  
    4224 Scale(=Guinier scale, G) 
    4225  
    4226 |cm^-1| 
    4227  
    4228 1.0 
    4229  
    4230 rg 
    4231  
    4232  
    4233  
    4234 100 
    4235  
    4236 dim(=Dimensional Variable, s) 
    4237  
    4238 1 
    4239  
    4240 m(=Porod exponent) 
    4241  
    4242 3 
    4243  
    4244 background 
    4245  
    4246 0.1 
    4247  
    4248  
    4249  
    4250 * * 
     3859Press (1982). Check out Chapter 4 on Data Treatment, pages 155-156.  
     3860 
     3861For 2D plot, the wave transfer is defined as 
     3862 
     3863.. image:: img/image008.PNG 
     3864 
     3865==============  ========  ============= 
     3866Parameter name  Units     Default value 
     3867==============  ========  ============= 
     3868| Scale(=Guinier scale,   | cm-1 1.0  
     3869| G)             
     3870 
     3871| rg   Ãƒâ€Š    100  
     3872 
     3873| dim(=Dimensional        |      1    
     3874| Variable, s)            |           
     3875 
     3876| m(=Porod exponent)      |      3    
     3877 
     3878| background              |      0.1  
     3879==============  ========  ============= 
     3880 
     3881.. image:: img/image196.JPG 
    42513882 
    42523883*Figure. 1D plot using the default values (w/500 data points).* 
     
    42543885 
    42553886 
    4256  
    4257  
    4258 *3.17. PorodModel* 
     3887.. _PorodModel: 
     3888 
     3889**2.2.17. PorodModel** 
    42593890 
    42603891A Porod analysis is done by linearizing the data at high q by plotting 
     
    42623893following model: 
    42633894 
    4264  
    4265  
    4266  
    4267  
    4268 C is the scale factor and Sv is the specific surface area of the 
    4269 sample and is the contrast factor. 
     3895.. image:: img/image197.PNG 
     3896 
     3897C is the scale factor and  Sv is the specific surface area of the sample 
     3898and ΔÏᅵ is the contrast factor. 
    42703899 
    42713900The background term is added for data analysis. 
    42723901 
    4273 For 2D plot, the wave transfer is defined as . 
    4274  
    4275  
    4276  
    4277 Parameter name 
    4278  
    4279 Units 
    4280  
    4281 Default value 
    4282  
    4283 scale 
    4284  
    4285 -4 
    4286  
    4287 0.1 
    4288  
    4289 background 
    4290  
    4291 |cm^-1| 
    4292  
    4293 0 
    4294  
    4295 *3.18. PeakGaussModel* 
     3902For 2D plot, the wave transfer is defined as 
     3903 
     3904.. image:: img/image040.GIF 
     3905 
     3906==============  ========  ============= 
     3907Parameter name  Units     Default value 
     3908==============  ========  ============= 
     3909| scale Ã -4  0.1  
     3910 
     3911| background              | cm-1 0    
     3912==============  ========  ============= 
     3913 
     3914 
     3915 
     3916.. _PeakGaussModel: 
     3917 
     3918**2.2.18. PeakGaussModel** 
    42963919 
    42973920Model describes a Gaussian shaped peak including a flat background, 
    42983921 
    4299  
    4300  
    4301  
    4302  
    4303  
     3922.. image:: img/image198.PNG 
    43043923 
    43053924with the peak having height of I0 centered at qpk having standard 
    4306 deviation of B. The fwhm is 2.354*B. 
     3925deviation of B.  The fwhm is 2.354\*B.   
    43073926 
    43083927Parameters I0, B, qpk, and BGD can all be adjusted during fitting. 
     
    43103929REFERENCE 
    43113930 
    4312 *None* 
    4313  
    4314 For 2D plot, the wave transfer is defined as . 
    4315  
    4316  
    4317  
    4318 Parameter name 
    4319  
    4320 Units 
    4321  
    4322 Default value 
    4323  
    4324 scale 
    4325  
    4326 |cm^-1| 
    4327  
    4328 100 
    4329  
    4330 q0 
    4331  
    4332  
    4333  
    4334 0.05 
    4335  
    4336 B 
    4337  
    4338 0.005 
    4339  
    4340 background 
    4341  
    4342 1 
    4343  
    4344  
    4345  
    4346  
    4347  
    4348 * * 
     3931None 
     3932 
     3933For 2D plot, the wave transfer is defined as 
     3934 
     3935.. image:: img/image040.GIF 
     3936 
     3937==============  ========  ============= 
     3938Parameter name  Units     Default value 
     3939==============  ========  ============= 
     3940| scale cm-1 100  
     3941 
     3942| q0   Ãƒâ€Š    0.05 
     3943 
     3944| B         0.005 
     3945 
     3946| background              |      1    
     3947==============  ========  ============= 
     3948 
     3949.. image:: img/image199.JPG 
    43493950 
    43503951*Figure. 1D plot using the default values (w/500 data points).* 
     
    43523953 
    43533954 
    4354 *3.19. PeakLorentzModel* 
     3955.. _PeakLorentzModel: 
     3956 
     3957**2.2.19. PeakLorentzModel** 
    43553958 
    43563959Model describes a Lorentzian shaped peak including a flat background, 
    43573960 
    4358  
    4359  
    4360  
    4361  
    4362  
    4363  
    4364 with the peak having height of I0 centered at qpk having a hwhm (half- 
    4365 width-half-maximum) of B. 
     3961.. image:: img/image200.PNG 
     3962 
     3963with the peak having height of I0 centered at qpk having a hwhm 
     3964(half-width-half-maximum) of B.  
    43663965 
    43673966The parameters I0, B, qpk, and BGD can all be adjusted during fitting. 
     
    43693968REFERENCE 
    43703969 
    4371 *None* 
    4372  
    4373 For 2D plot, the wave transfer is defined as . 
    4374  
    4375  
    4376  
    4377 Parameter name 
    4378  
    4379 Units 
    4380  
    4381 Default value 
    4382  
    4383 scale 
    4384  
    4385 |cm^-1| 
    4386  
    4387 100 
    4388  
    4389 q0 
    4390  
    4391  
    4392  
    4393 0.05 
    4394  
    4395 B 
    4396  
    4397 0.005 
    4398  
    4399 background 
    4400  
    4401 1 
    4402  
    4403  
    4404  
    4405  
    4406  
     3970None 
     3971 
     3972For 2D plot, the wave transfer is defined as 
     3973 
     3974.. image:: img/image040.GIF 
     3975 
     3976==============  ========  ============= 
     3977Parameter name  Units     Default value 
     3978==============  ========  ============= 
     3979| scale cm-1 100  
     3980 
     3981| q0   Ãƒâ€Š    0.05 
     3982 
     3983| B         0.005 
     3984 
     3985| background              |      1    
     3986==============  ========  ============= 
     3987 
     3988.. image:: img/image201.JPG 
    44073989 
    44083990*Figure. 1D plot using the default values (w/500 data points).* 
    44093991 
    4410 *3.20. Poly_GaussCoil (Model)* 
     3992 
     3993 
     3994.. _Poly_GaussCoil: 
     3995 
     3996**2.2.20. Poly_GaussCoil (Model)** 
    44113997 
    44123998Polydisperse Gaussian Coil: Calculate an empirical functional form for 
    44133999scattering from a polydisperse polymer chain ina good solvent. The 
    44144000polymer is polydisperse with a Schulz-Zimm polydispersity of the 
    4415 molecular weight distribution. 
    4416  
    4417 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    4418  
    4419  
     4001molecular weight distribution.  
     4002 
     4003The returned value is scaled to units of |cm^-1|, absolute scale. 
     4004 
     4005.. image:: img/image202.PNG 
    44204006 
    44214007where the dimensionless chain dimension is: 
    44224008 
    4423  
     4009.. image:: img/image203.PNG 
    44244010 
    44254011and the polydispersion is 
    44264012 
    4427 . 
    4428  
    4429 The scattering intensity I(q) is calculated as: 
     4013.. image:: img/image204.PNG 
     4014 
     4015The scattering intensity *I(q)* is calculated as: 
    44304016 
    44314017The polydispersion in rg is provided. 
    44324018 
    4433  
    4434  
    4435 For 2D plot, the wave transfer is defined as . 
    4436  
    4437  
    4438  
    4439 This example dataset is produced by running the Poly_GaussCoil, using 
    4440 200 data points, *qmin* = 0.001 |Ang^-1|, *qmax* = 0.7 -1 and the default values 
    4441 below. 
    4442  
    4443 Parameter name 
    4444  
    4445 Units 
    4446  
    4447 Default value 
    4448  
    4449 Scale 
    4450  
    4451 None 
    4452  
    4453 1.0 
    4454  
    4455 rg 
    4456  
    4457  
    4458  
    4459 60.0 
    4460  
    4461 poly_m 
    4462  
    4463 Mw/Mn 
    4464  
    4465 2 
    4466  
    4467 background 
    4468  
    4469 |cm^-1| 
    4470  
    4471 0.001 
    4472  
    4473  
    4474  
    4475  
     4019For 2D plot, the wave transfer is defined as 
     4020 
     4021.. image:: img/image040.GIF 
     4022 
     4023TEST DATASET 
     4024 
     4025 This example dataset is produced by running the Poly\_GaussCoil, using 
     4026200 data points, qmin = 0.001 Ã -1,  qmax = 0.7 Ã -1   and the default 
     4027values below. 
     4028 
     4029==============  ========  ============= 
     4030Parameter name  Units     Default value 
     4031==============  ========  ============= 
     4032| Scale None 1.0  
     4033 
     4034| rg   Ãƒâ€Š    60.0 
     4035 
     4036| poly\_m Mw/Mn 2    
     4037 
     4038| background              | cm-1 0.001 
     4039==============  ========  ============= 
     4040 
     4041.. image:: img/image205.JPG 
    44764042 
    44774043*Figure. 1D plot using the default values (w/200 data point).* 
    44784044 
    4479  
    4480  
    44814045REFERENCE 
    44824046 
    44834047Glatter & Kratky - pg.404. 
    44844048 
    4485 J.S. Higgins, and H.C. Benoit, Polymers and Neutron Scattering, Oxford Science Publications (1996). 
    4486  
    4487 *3.21. PolymerExclVolume (Model)* 
     4049J.S. Higgins, and H.C. Benoit, Polymers and Neutron Scattering, Oxford 
     4050Science Publications (1996). 
     4051 
     4052 
     4053 
     4054.. _PolyExclVolume: 
     4055 
     4056**2.2.21. PolymerExclVolume (Model)** 
    44884057 
    44894058Calculates the scattering from polymers with excluded volume effects. 
    44904059 
    4491 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
     4060The returned value is scaled to units of |cm^-1|, absolute scale. 
    44924061 
    44934062The returned value is P(Q) as written in equation (2), plus the 
    4494 incoherent background term. The result is in the units of |cm^-1|\ |sr^-1|, 
     4063incoherent background term. The result is in the units of |cm^-1|, 
    44954064absolute scale. 
    44964065 
    4497 A model describing polymer chain conformations with excluded volume 
    4498 was introduced to describe the conformation of polymer chains, and has 
    4499 been used as a template for describing mass fractals. The form factor 
    4500 for that model (Benoit, 1957) was originally presented in the 
    4501 following integral form: 
    4502  
    4503 (1) 
     4066A model describing polymer chain conformations with excluded volume was 
     4067introduced to describe the conformation of polymer chains, and has been 
     4068used as a template for describing mass fractals. The form factor for 
     4069that model (Benoit, 1957) was originally presented in the following 
     4070integral form: 
     4071 
     4072.. image:: img/image206.JPG     (1) 
    45044073 
    45054074Here n is the excluded volume parameter which is related to the Porod 
    4506 exponent m as n = 1/m, a is the polymer chain statistical segment 
    4507 length and n is the degree of polymerization. This integral was later 
    4508 put into an almost analytical form (Hammouda, 1993) as follows: 
    4509  
    4510 (2) 
     4075exponent m as n = 1/m, a is the polymer chain statistical segment length 
     4076and n is the degree of polymerization. This integral was later put into 
     4077an almost analytical form (Hammouda, 1993) as follows: 
     4078 
     4079.. image:: img/image207.JPG    (2) 
    45114080 
    45124081Here, g(x,U) is the incomplete gamma function which is a built-in 
    45134082function in computer libraries. 
    45144083 
    4515  
     4084.. image:: img/image208.JPG 
    45164085 
    45174086The variable U is given in terms of the scattering variable Q as: 
    45184087 
    4519  
     4088.. image:: img/image209.JPG 
    45204089 
    45214090The radius of gyration squared has been defined as: 
    45224091 
    4523  
     4092.. image:: img/image210.JPG 
    45244093 
    45254094Note that this model describing polymer chains with excluded volume 
    45264095applies only in the mass fractal range ( 5/3 <= m <= 3) and does not 
    4527 apply to surface fractals ( 3 < m <= 4). It does not reproduce the 
    4528 rigid rod limit (m = 1) because it assumes chain flexibility from the 
    4529 outset. It may cover a portion of the semiflexible chain range ( 1 < m 
    4530 < 5/3). 
     4096apply to surface fractals ( 3 < m <= 4). It does not reproduce the rigid 
     4097rod limit (m = 1) because it assumes chain flexibility from the outset.  
     4098It may cover a portion of the semiflexible chain range ( 1 < m < 5/3). 
    45314099 
    45324100The low-Q expansion yields the Guinier form and the high-Q expansion 
    45334101yields the Porod form which is given by: 
    45344102 
    4535  
     4103.. image:: img/image211.JPG 
    45364104 
    45374105Here G(x) = g(x,inf) is the gamma function. The asymptotic limit is 
    45384106dominated by the first term: 
    45394107 
    4540  
     4108.. image:: img/image212.JPG 
    45414109 
    45424110The special case when n = 0.5 (or m = 1/n = 2) corresponds to Gaussian 
     
    45444112function. 
    45454113 
    4546  
    4547  
    4548 The form factor given by Eq. 2 is the calculated result, and is 
    4549 plotted below for the default parameter values. 
     4114.. image:: img/image213.JPG 
     4115 
     4116The form factor given by Eq. 2 is the calculated result, and is plotted 
     4117below for the default parameter values. 
    45504118 
    45514119REFERENCE 
     
    45534121Benoit, H., Comptes Rendus (1957). 245, 2244-2247. 
    45544122 
    4555 Hammouda, B., SANS from Homogeneous Polymer Mixtures A Unified Overview, Advances in Polym. Sci. (1993), 106, 87-133. 
    4556  
    4557 For 2D plot, the wave transfer is defined as . 
    4558  
    4559  
    4560  
    4561 This example dataset is produced, using 200 data points, *qmin* = 0.001 
    4562 -1, *qmax* = 0.2 -1 and the default values below. 
    4563  
    4564 Parameter name 
    4565  
    4566 Units 
    4567  
    4568 Default value 
    4569  
    4570 Scale 
    4571  
    4572 None 
    4573  
    4574 1.0 
    4575  
    4576 rg 
    4577  
    4578  
    4579  
    4580 60.0 
    4581  
    4582 m(=Porod exponent) 
    4583  
    4584 3 
    4585  
    4586 background 
    4587  
    4588 |cm^-1| 
    4589  
    4590 0.0 
    4591  
    4592  
    4593  
    4594  
     4123Hammouda, B., SANS from Homogeneous Polymer Mixtures ­ A Unified 
     4124Overview, Advances in Polym. Sci. (1993), 106, 87-133. 
     4125 
     4126For 2D plot, the wave transfer is defined as 
     4127 
     4128.. image:: img/image040.GIF 
     4129 
     4130TEST DATASET 
     4131 
     4132 This example dataset is produced, using 200 data points, qmin = 0.001 
     4133Ã -1,  qmax = 0.2 Ã -1   and the default values below. 
     4134 
     4135==============  ========  ============= 
     4136Parameter name  Units     Default value 
     4137==============  ========  ============= 
     4138| Scale None 1.0  
     4139 
     4140| rg   Ãƒâ€Š    60.0 
     4141 
     4142| m(=Porod exponent)      |      3    
     4143 
     4144| background              | cm-1 0.0  
     4145==============  ========  ============= 
     4146 
     4147.. image:: img/image214.JPG 
    45954148 
    45964149*Figure. 1D plot using the default values (w/500 data points).* 
     
    45984151 
    45994152 
    4600 *3.22.  RPA10Model* 
     4153.. _RPA10Model: 
     4154 
     4155**2.2.22. RPA10Model** 
    46014156 
    46024157Calculates the macroscopic scattering intensity (units of cm^-1) for a 
     
    46244179Case 9: A-B-C-D Four-block copolymer 
    46254180 
    4626 NB: the case numbers are different from the IGOR/NIST SANS package. 
    4627  
    4628  
    4629  
    4630 Only one case can be used at any one time. Plotting a different case 
     4181Note: the case numbers are different from the IGOR/NIST SANS package. 
     4182 
     4183Only one case can be used at any one time.  Plotting a different case 
    46314184will overwrite the original parameter waves. 
    46324185 
    4633 The returned value is scaled to units of |cm^-1|. 
     4186The returned value is scaled to units of [cm-1]. 
    46344187 
    46354188Component D is assumed to be the "background" component (all contrasts 
    46364189are calculated with respect to component D). 
    46374190 
    4638 Scattering contrast for a C/D blend= {SLD (component C) - SLD 
    4639 (component D)}2 
    4640  
    4641 Depending on what case is used, the number of fitting parameters 
    4642 varies. These represent the segment lengths (ba, bb, etc) and the Chi 
    4643 parameters (Kab, Kac, etc). The last one of these is a scaling factor 
    4644 to be held constant equal to unity. 
     4191Scattering contrast for a C/D blend= {SLD (component C) - SLD (component 
     4192D)}2 
     4193 
     4194Depending on what case is used, the number of fitting parameters varies. 
     4195These represent the segment lengths (ba, bb, etc) and the Chi parameters 
     4196(Kab, Kac, etc). The last one of these is a scaling factor to be held 
     4197constant equal to unity. 
    46454198 
    46464199The input parameters are the degree of polymerization, the volume 
     
    46554208A.Z. Akcasu, R. Klein and B. Hammouda, Macromolecules 26, 4136 (1993) 
    46564209 
    4657  
    4658  
    46594210Fitting parameters for Case0 Model 
    46604211 
    4661 Parameter name 
    4662  
    4663 Units 
    4664  
    4665 Default value 
    4666  
    4667 background 
    4668  
    4669 |cm^-1| 
    4670  
    4671 0.0 
    4672  
    4673 scale 
    4674  
    4675 1 
    4676  
    4677 bc(=Seg. Length bc) 
    4678  
    4679 5 
    4680  
    4681 bd(=Seg. Length bd) 
    4682  
    4683 5 
    4684  
    4685 Kcd(Chi Param. Kcd) 
    4686  
    4687 -0.0004 
    4688  
    4689  
    4690  
    4691  
     4212==============  ========  ============= 
     4213Parameter name  Units     Default value 
     4214==============  ========  ============= 
     4215| background              | cm-1 0.0  
     4216 
     4217| scale      1    
     4218 
     4219| bc(=Seg. Length bc)     |      5    
     4220 
     4221| bd(=Seg. Length bd)     |      5    
     4222 
     4223| Kcd(Chi Param. Kcd)     |      -0.0004 
     4224==============  ========  ============= 
    46924225 
    46934226Fixed parameters for Case0 Model 
    46944227 
    4695 Parameter name 
    4696  
    4697 Units 
    4698  
    4699 Default value 
    4700  
    4701 Lc(= Scatter. Length_c) 
    4702  
    4703 1e-12 
    4704  
    4705 Ld(= Scatter. Length_d) 
    4706  
    4707 0 
    4708  
    4709 Nc(=Deg.Polym.c) 
    4710  
    4711 1000 
    4712  
    4713 Nd(=Deg.Polym.d) 
    4714  
    4715 1000 
    4716  
    4717 Phic(=Vol. fraction of c) 
    4718  
    4719 0.25 
    4720  
    4721 Phid(=Vol. fraction of d) 
    4722  
    4723 0.25 
    4724  
    4725 vc(=Spec. vol. of c) 
    4726  
    4727 100 
    4728  
    4729 vd(=Spec. vol. of d) 
    4730  
    4731 100 
    4732  
    4733  
    4734  
    4735  
    4736  
    4737  
     4228==============  ========  ============= 
     4229Parameter name  Units     Default value 
     4230==============  ========  ============= 
     4231| Lc(= Scatter.           |      1e-12 
     4232| Length\_c)              |           
     4233 
     4234| Ld(= Scatter.           |      0    
     4235| Length\_d)              |           
     4236 
     4237| Nc(=Deg.Polym.c)        |      1000 
     4238 
     4239| Nd(=Deg.Polym.d)        |      1000 
     4240 
     4241| Phic(=Vol. fraction of  |      0.25 
     4242| c)             
     4243 
     4244| Phid(=Vol. fraction of  |      0.25 
     4245| d)             
     4246 
     4247| vc(=Spec. vol. of c)    |      100  
     4248 
     4249| vd(=Spec. vol. of d)    |      100  
     4250==============  ========  ============= 
     4251 
     4252.. image:: img/image215.JPG 
    47384253 
    47394254*Figure. 1D plot using the default values (w/500 data points).* 
     
    47414256 
    47424257 
    4743 *3.23. TwoLorentzian(Model)* 
    4744  
    4745 Calculate an empirical functional form for SANS data characterized by 
    4746 a two Lorentzian functions. 
    4747  
    4748 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    4749  
    4750 The scattering intensity I(q) is calculated by: 
    4751  
    4752  
    4753  
    4754  
     4258 
     4259.. _TwoLorentzian: 
     4260 
     4261**2.2.23. TwoLorentzian(Model)** 
     4262 
     4263Calculate an empirical functional form for SANS data characterized by a 
     4264two Lorentzian functions. 
     4265 
     4266The returned value is scaled to units of |cm^-1|, absolute scale. 
     4267 
     4268The scattering intensity *I(q)* is calculated by:  
     4269 
     4270.. image:: img/image216.JPG  
    47554271 
    47564272A = Lorentzian scale #1 
    47574273 
    4758 C = Lorentzian scale #2 
     4274C = Lorentzian scale #2  
    47594275 
    47604276where scale is the peak height centered at q0, and B refers to the 
     
    47634279The background term is added for data analysis. 
    47644280 
    4765 For 2D plot, the wave transfer is defined as . 
    4766  
    4767 *Default input parameter values* 
    4768  
    4769 Parameter name 
    4770  
    4771 Units 
    4772  
    4773 Default value 
    4774  
    4775 scale_1(=A) 
    4776  
    4777 10 
    4778  
    4779 scale_2(=C) 
    4780  
    4781 1 
    4782  
    4783 1ength_1 (=Correlation length1) 
    4784  
    4785  
    4786  
    4787 100 
    4788  
    4789 1ength_2(=Correlation length2) 
    4790  
    4791  
    4792  
    4793 10 
    4794  
    4795 exponent_1(=n) 
    4796  
    4797 3 
    4798  
    4799 exponent_2(=m) 
    4800  
    4801 2 
    4802  
    4803 Background(=B) 
    4804  
    4805 |cm^-1| 
    4806  
    4807 0.1 
    4808  
    4809  
    4810  
    4811  
    4812  
    4813  
     4281For 2D plot, the wave transfer is defined as 
     4282 
     4283.. image:: img/image040.GIF 
     4284 
     4285**Default input parameter values** 
     4286 
     4287==============  ========  ============= 
     4288Parameter name  Units     Default value 
     4289==============  ========  ============= 
     4290| scale\_1(=A)            |      10   
     4291 
     4292| scale\_2(=C)            |      1    
     4293 
     4294| 1ength\_1 (=Correlation | Ã     100  
     4295| length1)                |           
     4296 
     4297| 1ength\_2(=Correlation  | Ã     10   
     4298| length2)                |           
     4299 
     4300| exponent\_1(=n)         |      3    
     4301 
     4302| exponent\_2(=m)         |      2    
     4303 
     4304| Background(=B)          | cm-1 0.1  
     4305==============  ========  ============= 
     4306 
     4307.. image:: img/image217.JPG 
    48144308 
    48154309*Figure. 1D plot using the default values (w/500 data points).* 
    48164310 
    4817  
    4818  
    4819 REFERENCE 
    4820  
    4821 *None* 
    4822  
    4823 *3.24. TwoPowerLaw(Model)* 
     4311REFERENCE 
     4312 
     4313None 
     4314 
     4315 
     4316 
     4317.. _TwoPowerLaw: 
     4318 
     4319**2.2.24. TwoPowerLaw(Model)** 
    48244320 
    48254321Calculate an empirical functional form for SANS data characterized by 
    48264322two power laws. 
    48274323 
    4828 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    4829  
    4830  
    4831  
    4832 The scattering intensity I(q) is calculated by: 
    4833  
    4834  
    4835  
    4836  
     4324The returned value is scaled to units of |cm^-1|, absolute scale. 
     4325 
     4326The scattering intensity *I(q)* is calculated by: 
     4327 
     4328.. image:: img/image218.JPG 
    48374329 
    48384330qc is the location of the crossover from one slope to the other. The 
    48394331scaling A, sets the overall intensity of the lower Q power law region. 
    4840 The scaling of the second power law region is scaled to match the 
    4841 first. Be sure to enter the power law exponents as positive values. 
    4842  
    4843 For 2D plot, the wave transfer is defined as . 
    4844  
    4845 *Default input parameter values* 
    4846  
    4847 Parameter name 
    4848  
    4849 Units 
    4850  
    4851 Default value 
    4852  
    4853 coef_A 
    4854  
    4855 1.0 
    4856  
    4857 qc 
    4858  
    4859 -1 
    4860  
    4861 0.04 
    4862  
    4863 power_1(=m1) 
    4864  
    4865 4 
    4866  
    4867 power_2(=m2) 
    4868  
    4869 4 
    4870  
    4871 background 
    4872  
    4873 |cm^-1| 
    4874  
    4875 0.0 
    4876  
    4877  
    4878  
    4879  
    4880  
    4881  
     4332The scaling of the second power law region is scaled to match the first. 
     4333Be sure to enter the power law exponents as positive values. 
     4334 
     4335For 2D plot, the wave transfer is defined as 
     4336 
     4337.. image:: img/image040.GIF 
     4338 
     4339**Default input parameter values** 
     4340 
     4341==============  ========  ============= 
     4342Parameter name  Units     Default value 
     4343==============  ========  ============= 
     4344| coef\_A      1.0  
     4345 
     4346| qc   Ãƒâ€Š-1  0.04 
     4347 
     4348| power\_1(=m1)           |      4    
     4349 
     4350| power\_2(=m2)           |      4    
     4351 
     4352| background              | cm-1 0.0  
     4353==============  ========  ============= 
     4354 
     4355.. image:: img/image219.JPG 
    48824356 
    48834357*Figure. 1D plot using the default values (w/500 data points).* 
     
    48854359 
    48864360 
    4887 *3.25. UnifiedPower(Law and)Rg(Model)* 
    4888  
    4889 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    4890  
    4891 Note that the level 0 is an extra function that is the inverse 
    4892 function; I (q) = scale/q + background. 
     4361.. _UnifiedPowerRg: 
     4362 
     4363**2.2.25. UnifiedPower(Law and)Rg(Model)** 
     4364 
     4365The returned value is scaled to units of |cm^-1|, absolute scale.  
     4366 
     4367Note that the level 0 is an extra function that is the inverse function; 
     4368I (q) = scale/q + background. 
    48934369 
    48944370Otherwise, program incorporates the empirical multiple level unified 
     
    48994375The empirical expressions are able to reasonably approximate the 
    49004376scattering from many different types of particles, including fractal 
    4901 clusters, random coils (Debye equation), ellipsoidal particles, etc. 
    4902 The empirical fit function is 
    4903  
    4904  
    4905  
    4906  
    4907  
    4908 For each level, the four parameters Gi, Rg,i, Bi and Pi must be 
    4909 chosen. 
     4377clusters, random coils (Debye equation), ellipsoidal particles, etc.  
     4378The empirical fit function is  
     4379 
     4380.. image:: img/image220.JPG 
     4381 
     4382For each level, the four parameters Gi, Rg,i, Bi and Pi must be chosen.  
    49104383 
    49114384For example, to approximate the scattering from random coils (Debye 
    4912 equation), set Rg,i as the Guinier radius, Pi = 2, and Bi = 2 Gi / 
    4913 Rg,i 
     4385equation), set Rg,i as the Guinier radius, Pi = 2, and Bi = 2 Gi / Rg,i  
    49144386 
    49154387See the listed references for further information on choosing the 
    49164388parameters. 
    49174389 
    4918  
    4919  
    4920 For 2D plot, the wave transfer is defined as . 
    4921  
    4922 *Default input parameter values* 
    4923  
    4924 Parameter name 
    4925  
    4926 Units 
    4927  
    4928 Default value 
    4929  
    4930 scale 
    4931  
    4932 1.0 
    4933  
    4934 Rg2 
    4935  
    4936  
    4937  
    4938 21 
    4939  
    4940 power2 
    4941  
    4942 2 
    4943  
    4944 G2 
    4945  
    4946 |cm^-1|\ |sr^-1| 
    4947  
    4948 3 
    4949  
    4950 B2 
    4951  
    4952 |cm^-1|\ |sr^-1| 
    4953  
    4954 0.0006 
    4955  
    4956 Rg1 
    4957  
    4958  
    4959  
    4960 15.8 
    4961  
    4962 power1 
    4963  
    4964 4 
    4965  
    4966 G1 
    4967  
    4968 |cm^-1|\ |sr^-1| 
    4969  
    4970 400 
    4971  
    4972 B1 
    4973  
    4974 |cm^-1|\ |sr^-1| 
    4975  
    4976 4.5e-006 
    4977  
    4978 background 
    4979  
    4980 |cm^-1| 
    4981  
    4982 0.0 
    4983  
    4984  
    4985  
    4986  
    4987  
    4988  
     4390For 2D plot, the wave transfer is defined as 
     4391 
     4392.. image:: img/image040.GIF 
     4393 
     4394**Default input parameter values** 
     4395 
     4396==============  ========  ============= 
     4397Parameter name  Units     Default value 
     4398==============  ========  ============= 
     4399| scale      1.0  
     4400 
     4401| Rg2  Ã     21   
     4402 
     4403| power2      2    
     4404 
     4405| G2   cm-1sr-1                | 3    
     4406 
     4407| B2   cm-1sr-1                | 0.0006 
     4408 
     4409| Rg1  Ã     15.8 
     4410 
     4411| power1      4    
     4412 
     4413| G1   cm-1sr-1                | 400  
     4414 
     4415| B1   cm-1sr-1                | 4.5e-006                | 
     4416 
     4417| background              | cm-1 0.0  
     4418==============  ========  ============= 
     4419 
     4420.. image:: img/image221.JPG 
    49894421 
    49904422*Figure. 1D plot using the default values (w/500 data points).* 
    49914423 
    4992  
    4993  
    4994 REFERENCE 
    4995  
    4996 G. Beaucage (1995). J. Appl. Cryst., vol. 28, p717-728. 
    4997  
    4998 G. Beaucage (1996). J. Appl. Cryst., vol. 29, p134-146. 
    4999  
    5000 *3.26.  LineModel* 
     4424REFERENCE 
     4425 
     4426G. Beaucage (1995).  J. Appl. Cryst., vol. 28, p717-728. 
     4427 
     4428G. Beaucage (1996).  J. Appl. Cryst., vol. 29, p134-146. 
     4429 
     4430 
     4431 
     4432.. _LineModel: 
     4433 
     4434**2.2.26. LineModel** 
    50014435 
    50024436This is a linear function that calculates: 
    50034437 
    5004  
    5005  
    5006  
    5007  
    5008 where A and B are the coefficients of the first and second order 
    5009 terms. 
    5010  
    5011 *NB:* For 2D plot, I(q) = I(qx)*I(qy) which is defined differently 
     4438.. image:: img/image222.PNG 
     4439 
     4440where A and B are the coefficients of the first and second order terms. 
     4441 
     4442**Note:** For 2D plot, *I(q)*= I(qx)\*I(qy)  which is defined differently 
    50124443from other shape independent models. 
    50134444 
    5014 Parameter name 
    5015  
    5016 Units 
    5017  
    5018 Default value 
    5019  
    5020 A 
    5021  
    5022 |cm^-1| 
    5023  
    5024 1.0 
    5025  
    5026 B 
    5027  
    5028  
    5029  
    5030 1.0 
    5031  
    5032  
    5033  
    5034 *3.27. ReflectivityModel* 
     4445==============  ========  ============= 
     4446Parameter name  Units     Default value 
     4447==============  ========  ============= 
     4448| A    cm-1 1.0  
     4449 
     4450| B    Ã     1.0  
     4451==============  ========  ============= 
     4452 
     4453 
     4454 
     4455.. _ReflectivityModel: 
     4456 
     4457**2.2.27. ReflectivityModel** 
    50354458 
    50364459This model calculates the reflectivity and uses the Parrett algorithm. 
    50374460Up to nine film layers are supported between Bottom(substrate) and 
    50384461Medium(Superstrate where the neutron enters the first top film). Each 
    5039 layers are composed of [ of the interface(from the previous layer or 
    5040 substrate) + flat portion + of the interface(to the next layer or 
     4462layers are composed of [ Âœ of the interface(from the previous layer or 
     4463substrate) + flat portion + Âœ of the interface(to the next layer or 
    50414464medium)]. Only two simple interfacial functions are selectable, error 
    50424465function and linear function. The each interfacial thickness is 
     
    50444467sigma=roughness). 
    50454468 
    5046 NB: This model was contributed by an interested user. 
    5047  
    5048  
    5049  
    5050 *Figure. Comparison (using the SLD profile below) with NISTweb 
    5051 calculation (circles): 
    5052 http://www.ncnr.nist.gov/resources/reflcalc.html.* 
    5053  
    5054  
     4469Note: This model was contributed by an interested user. 
     4470 
     4471.. image:: img/image231.BMP 
     4472 
     4473*Figure. Comparison (using the SLD profile below) with NISTweb calculation (circles)* 
     4474http://www.ncnr.nist.gov/resources/reflcalc.html 
     4475 
     4476.. image:: img/image232.GIF 
    50554477 
    50564478*Figure. SLD profile used for the calculation(above).* 
    50574479 
    5058 *3.28. ReflectivityIIModel* 
    5059  
    5060 Same as the ReflectivityModel except that the it is more customizable. 
    5061 More interfacial functions are supplied. The number of points 
    5062 (npts_inter) for each interface can be choosen. The constant (A below 
    5063 but 'nu' as a parameter name of the model) for exp, erf, or power-law 
    5064 is an input. The SLD at the interface between layers, *rinter_i*, is 
    5065 calculated with a function chosen by a user, where the functions are: 
     4480 
     4481 
     4482.. _ReflectivityIIModel: 
     4483 
     4484**2.2.28. ReflectivityIIModel** 
     4485 
     4486    Same as the ReflectivityModel except that the it is more 
     4487customizable. More interfacial functions are supplied. The number of 
     4488points (npts\_inter) for each interface can be choosen.     The constant 
     4489(A below but 'nu' as a parameter name of the model) for exp, erf, or 
     4490power-law is an input. The SLD at the interface between layers, 
     4491*rinter\_i*, is calculated with a function chosen by a user, where the 
     4492functions are: 
    50664493 
    506744941) Erf; 
    50684495 
    5069  
     4496.. image:: img/image051.GIF 
    50704497 
    507144982) Power-Law; 
    50724499 
    5073  
    5074  
    5075  
    5076  
    5077  
     4500.. image:: img/image050.GIF 
    50784501 
    507945023) Exp; 
    50804503 
    5081  
    5082  
    5083  
    5084  
    5085 NB: This model was implemented by an interested user. 
    5086  
    5087 *3.29. GelFitModel* 
    5088  
    5089 Unlike a concentrated polymer solution, the fine-scale polymer 
     4504.. image:: img/image049.GIF 
     4505 
     4506    Note: This model was implemented by an interested user. 
     4507 
     4508 
     4509 
     4510.. _GelFitModel: 
     4511 
     4512**2.2.29. GelFitModel** 
     4513 
     4514    Unlike a concentrated polymer solution, the fine-scale polymer 
    50904515distribution in a gel involves at least two characteristic length 
    50914516scales, a shorter correlation length (a1) to describe the rapid 
    50924517fluctuations in the position of the polymer chains that ensure 
    50934518thermodynamic equilibrium, and a longer distance (denoted here as a2) 
    5094 needed to account for the static accumulations of polymer pinned down 
    5095 by junction points or clusters of such points. The letter is derived 
    5096 from a simple Guinier function. 
    5097  
    5098 The scattered intensity I(Q) is then calculated as: 
    5099  
    5100  
     4519needed to account for the static accumulations of polymer pinned down by 
     4520junction points or clusters of such points. The letter is derived from a 
     4521simple Guinier function. 
     4522 
     4523The scattered intensity *I(q)* is then calculated as: 
     4524 
     4525.. image:: img/image233.GIF 
    51014526 
    51024527Where: 
    51034528 
    5104  
    5105  
    5106  
    5107  
    5108  
    5109  
    5110 Note the first term reduces to the Ornstein-Zernicke equation when 
    5111 D=2; ie, when the Flory exponent is 0.5 (theta conditions). In gels 
    5112 with significant hydrogen bonding D has been reported to be ~2.6 to 
    5113 2.8. 
    5114  
    5115 NB: This model was implemented by an interested user. 
    5116  
    5117 *Default input parameter values* 
    5118  
    5119 Parameter name 
    5120  
    5121 Units 
    5122  
    5123 Default value 
    5124  
    5125 Background 
    5126  
    5127 |cm^-1| 
    5128  
    5129 0.01 
    5130  
    5131 Guinier scale 
    5132  
    5133 |cm^-1| 
    5134  
    5135 1.7 
    5136  
    5137 Lorentzian scale 
    5138  
    5139 |cm^-1| 
    5140  
    5141 3.5 
    5142  
    5143 Radius of gyration 
    5144  
    5145  
    5146  
    5147 104 
    5148  
    5149 Fractal exponent 
    5150  
    5151 2 
    5152  
    5153 Correlation length 
    5154  
    5155  
    5156  
    5157 16 
    5158  
    5159  
    5160  
    5161  
    5162  
    5163  
     4529.. image:: img/image234.GIF 
     4530 
     4531    Note the first term reduces to the Ornstein-Zernicke equation when 
     4532D=2; ie, when the Flory exponent is 0.5 (theta conditions).   In gels 
     4533with significant hydrogen bonding D has been reported to be ~2.6 to 2.8. 
     4534 
     4535    Note: This model was implemented by an interested user. 
     4536 
     4537**Default input parameter values** 
     4538 
     4539==============  ========  ============= 
     4540Parameter name  Units     Default value 
     4541==============  ========  ============= 
     4542| Background              | cm-1 0.01 
     4543 
     4544| Guinier scale           | cm-1 1.7  
     4545 
     4546| Lorentzian scale        | cm-1 3.5  
     4547 
     4548| Radius of gyration      | Ã     104  
     4549 
     4550| Fractal exponent        |      2    
     4551 
     4552| Correlation length      | Ã     16   
     4553==============  ========  ============= 
     4554 
     4555.. image:: img/image235.GIF 
    51644556 
    51654557*Figure. 1D plot using the default values (w/300 data points, 
    5166 *qmin*=0.001, and *qmax*=0.3).* 
    5167  
    5168  
     4558qmin=0.001, and qmax=0.3).* 
    51694559 
    51704560REFERENCE 
     
    51784568 
    51794569 
    5180 **3.30. Star Polymer with Gaussian Statistics** 
     4570.. _StarPolymer: 
     4571 
     4572**2.2.30. Star Polymer with Gaussian Statistics** 
    51814573 
    51824574For a star with *f* arms: 
    51834575 
    5184  
    5185  
    5186  
    5187  
    5188  
     4576.. image:: img/star1.PNG 
     4577 
     4578.. image:: img/star2.PNG 
     4579 
     4580.. image:: img/star3.PNG 
    51894581 
    51904582where is the ensemble average radius of gyration squared of an arm. 
    51914583 
    5192  
    5193  
    5194 REFERENCE 
    5195  
    5196 H. Benoit, J. Polymer Science., 11, 596-599 (1953) 
    5197  
    5198  
    5199  
     4584REFERENCE 
     4585 
     4586H. Benoit,   J. Polymer Science.,  11, 596-599  (1953) 
    52004587 
    52014588 
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