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src/sans/models/media/model_functions.rst
rd4117ccb r4ed2d0a1 210 210 ------------------------------- 211 211 212 - AbsolutePower_Law 212 - AbsolutePower_Law_ 213 213 - BEPolyelectrolyte 214 214 - BroadPeakModel … … 1678 1678 1679 1679 W-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 â65481680 *Cationic Wormlike Micelles*. *Langmuir*, 22(15) 2006 6539ââ¬â6548 1681 1681 1682 1682 … … 1766 1766 1767 1767 W-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 â65481768 *Cationic Wormlike Micelles*. *Langmuir*, 22(15) 2006 6539ââ¬â6548 1769 1769 1770 1770 … … 1939 1939 .. image:: img/image079.GIF 1940 1940 1941 The scattering intensity I(q)is1941 The scattering intensity *I(q)* is 1942 1942 1943 1943 .. image:: img/image081.PNG … … 2421 2421 2422 2422 where |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). 2424 2424 2425 2425 The 2D scattering intensity is calculated in the same way as 1D, where the *q* vector is defined as … … 2454 2454 2455 2455 also in J. Phys. Chem. B, 105, (2001) 11081-11088 2456 2457 *2014/04/17 - Description reviewed by S. King and P. Butler.* 2456 2458 2457 2459 … … 2665 2667 *2.1.34.1. Definition* 2666 2668 2667 The scattering intensity I(q)is calculated as2669 The scattering intensity *I(q)* is calculated as 2668 2670 2669 2671 .. image:: img/image149.JPG … … 3120 3122 The following are models used for shape-independent SANS analysis. 3121 3123 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 3128 The Debye model is a form factor for a linear polymer chain. In addition 3129 to the radius of gyration, Rg, a scale factor "scale", and a constant 3130 background term are included in the calculation. 3131 3132 .. image:: img/image172.PNG 3133 3134 For 2D plot, the wave transfer is defined as 3135 3136 .. image:: img/image040.GIF 3137 3138 ============== ======== ============= 3139 Parameter name Units Default value 3140 3141 ============== ======== ============= 3142 | scale None 1.0 3143 3144 | rg Ã⊠50.0 3145 3146 | background | cm-1 0.0 3147 ============== ======== ============= 3148 3149 .. image:: img/image173.JPG 3163 3150 3164 3151 *Figure. 1D plot using the default values (w/200 data point).* 3165 3152 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 3153 REFERENCE 3154 3155 Roe, R.-J., "Methods of X-Ray and Neutron Scattering in 3156 Polymer Science", Oxford University Press, New York (2000). 3157 3158 3159 3160 .. _BroadPeakModel: 3161 3162 **2.2.2. BroadPeak Model** 3163 3164 Calculate an empirical functional form for SANS data characterized by a 3165 broad scattering peak. Many SANS spectra are characterized by a broad 3166 peak even though they are from amorphous soft materials. The d-spacing 3167 corresponding to the broad peak is a characteristic distance between the 3168 scattering inhomogeneities (such as in lamellar, cylindrical, or 3169 spherical morphologies or for bicontinuous structures). 3170 3171 The returned value is scaled to units of |cm^-1|, absolute scale. 3172 3173 The scattering intensity *I(q)* is calculated by: 3174 3175 .. image:: img/image174.JPG 3176 3177 Here the peak position is related to the d-spacing as Q0 = 2pi/d0. Soft 3178 systems that show a SANS peak include copolymers, polyelectrolytes, 3179 multiphase systems, layered structures, etc. 3180 3181 For 2D plot, the wave transfer is defined as 3182 3183 .. image:: img/image040.GIF 3184 3185 ============== ======== ============= 3186 Parameter 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) | ÃâŠ-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 3241 3204 3242 3205 *Figure. 1D plot using the default values (w/200 data point).* 3243 3206 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 3207 REFERENCE 3208 3209 None. 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 3219 Calculate an empirical functional form for SANS data characterized by a 3220 low-Q signal and a high-Q signal 3221 3222 The returned value is scaled to units of |cm^-1|, absolute scale. 3223 3224 The scattering intensity *I(q)* is calculated by: 3225 3226 .. image:: img/image176.JPG 3262 3227 3263 3228 The first term describes Porod scattering from clusters (exponent = n) 3264 and the second term is a Lorentzian function describing scattering 3265 frompolymer chains (exponent = m). This second term characterizes the3229 and the second term is a Lorentzian function describing scattering from 3230 polymer chains (exponent = m). This second term characterizes the 3266 3231 polymer/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 3232 multiplicative factors A and C, the incoherent background B and the two 3233 exponents 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 = 3235 2, this functional form becomes the familiar Lorentzian function. 3236 3237 For 2D plot, the wave transfer is defined as 3238 3239 .. image:: img/image040.GIF 3240 3241 ============== ======== ============= 3242 Parameter 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 3314 3258 3315 3259 *Figure. 1D plot using the default values (w/500 data points).* 3316 3260 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)* 3261 REFERENCE 3262 3263 B. Hammouda, D.L. Ho and S.R. Kline, Insight into Clustering in 3264 Poly(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)** 3327 3273 3328 3274 The Ornstein-Zernicke model is defined by: 3329 3275 3330 3331 3332 3333 3334 3276 .. image:: img/image178.PNG 3335 3277 3336 3278 The parameter L is referred to as the screening length. 3337 3279 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 * * 3280 For 2D plot, the wave transfer is defined as 3281 3282 .. image:: img/image040.GIF 3283 3284 ============== ======== ============= 3285 Parameter 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 3304 Calculates the scattering from a randomly distributed, two-phase system 3305 based on the Debye-Anderson-Brumberger (DAB) model for such systems. The 3306 two-phase system is characterized by a single length scale, the 3307 correlation length, which is a measure of the average spacing between 3308 regions of phase 1 and phase 2. The model also assumes smooth interfaces 3309 between the phases and hence exhibits Porod behavior (I ~ Q-4) at large 3310 Q (Q\*correlation length >> 1). 3311 3312 .. image:: img/image180.PNG 3313 3314 The parameter L is referred to as the correlation length. 3315 3316 For 2D plot, the wave transfer is defined as 3317 3318 .. image:: img/image040.GIF 3319 3320 ============== ======== ============= 3321 Parameter 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 3334 REFERENCE 3335 3336 Debye, Anderson, Brumberger, "Scattering by an Inhomogeneous Solid. II. 3337 The Correlation Function and its Application", J. Appl. Phys. 28 (6), 3338 679 (1957). 3339 3340 Debye, Bueche, "Scattering by an Inhomogeneous Solid", J. Appl. Phys. 3341 20, 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 3351 This model describes a power law with background. 3352 3353 .. image:: img/image182.PNG 3354 3355 Note the minus sign in front of the exponent. 3356 3357 ============== ======== ============= 3358 Parameter 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 3371 3368 3372 3369 *Figure. 1D plot using the default values (w/200 data point).* 3373 3370 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)** 3478 3376 3479 3377 This function calculates the scattered intensity of a two-component 3480 3378 system using the Teubner-Strey model. 3481 3379 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 3382 For 2D plot, the wave transfer is defined as 3383 3384 .. image:: img/image040.GIF 3385 3386 ============== ======== ============= 3387 Parameter 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 3525 3399 3526 3400 *Figure. 1D plot using the default values (w/200 data point).* … … 3528 3402 REFERENCE 3529 3403 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* 3404 Teubner, M; Strey, R. J. Chem. Phys., 87, 3195 (1987). 3405 3406 Schubert, K-V., Strey, R., Kline, S. R. and E. W. Kaler, J. Chem. Phys., 3407 101, 5343 (1994). 3408 3409 3410 3411 .. _FractalModel: 3412 3413 **2.2.8. FractalModel** 3538 3414 3539 3415 Calculates the scattering from fractal-like aggregates built from 3540 3416 spherical 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 3417 returned is in cm-1. 3418 3419 .. image:: img/image186.PNG 3420 3421 The scale parameter is the volume fraction of the building blocks, R0 is 3422 the radius of the building block, Df is the fractal dimension, ß is the 3423 correlation length, *Ãï¿œsolvent* is the scattering length density of the 3424 solvent, and *Ãï¿œblock* is the scattering length density of the building 3425 blocks. 3426 3427 **The polydispersion in radius is provided.** 3428 3429 For 2D plot, the wave transfer is defined as 3430 3431 .. image:: img/image040.GIF 3432 3433 ============== ======== ============= 3434 Parameter 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 | ÃâŠ-2 2e-6 3445 3446 | solvent\_sld | ÃâŠ-2 6e-6 3447 3448 | background | cm-1 0.0 3449 ============== ======== ============= 3450 3451 .. image:: img/image187.JPG 3610 3452 3611 3453 *Figure. 1D plot using the default values (w/200 data point).* 3612 3454 3613 3614 3615 3616 3617 3455 REFERENCE 3618 3456 … … 3621 3459 3622 3460 3623 *3.9. MassFractalModel* 3461 .. _MassFractalModel: 3462 3463 **2.2.9. MassFractalModel** 3624 3464 3625 3465 Calculates the scattering from fractal-like aggregates based on the 3626 Mildner reference (below). 3627 3628 3629 3630 3631 3632 3633 3634 3635 3466 Mildner reference (below). 3467 3468 .. image:: img/mass_fractal_eq1.JPG 3636 3469 3637 3470 The R is the radius of the building block, Dm is the mass fractal 3638 dimension, is the correlation (or cutt-off) length, *solvent* is the3639 scattering length density of the solvent, and * particle* is the3471 dimension, ß is the correlation (or cutt-off) length, *Ãï¿œsolvent* is the 3472 scattering length density of the solvent, and *Ãï¿œparticle* is the 3640 3473 scattering length density of particles. 3641 3474 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 3475 Note:  The mass fractal dimension is valid for 1<mass\_dim<6. 3476 3477 ============== ======== ============= 3478 Parameter 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 3683 3492 3684 3493 *Figure. 1D plot* 3685 3494 3686 3687 3688 3689 3690 REFERENCE 3691 3692 D. Mildner, and P. Hall, J. Phys. D.: Appl. Phys., 19, 1535-1545 3495 REFERENCE 3496 3497 D. Mildner, and P. Hall, J. Phys. D.: Appl. Phys., 19, 1535-1545 3693 3498 (1986), Equation(9). 3694 3499 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 3508 Calculates the scattering based on the Mildner reference (below). 3509 3510 .. image:: img/surface_fractal_eq1.GIF 3713 3511 3714 3512 The R is the radius of the building block, Ds is the surface fractal 3715 dimension, is the correlation (or cutt-off) length, *solvent* is the3716 scattering length density of the solvent, and * particle* is the3513 dimension, ß is the correlation (or cutt-off) length, *Ãï¿œsolvent* is the 3514 scattering length density of the solvent, and *Ãï¿œparticle* is the 3717 3515 scattering length density of particles. 3718 3516 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 ============== ======== ============= 3521 Parameter 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 3761 3535 3762 3536 *Figure. 1D plot* 3763 3537 3764 3765 3766 3767 3768 REFERENCE 3769 3770 D. Mildner, and P. Hall, J. Phys. D.: Appl. Phys., 19, 1535-1545 3538 REFERENCE 3539 3540 D. Mildner, and P. Hall, J. Phys. D.: Appl. Phys., 19, 1535-1545 3771 3541 (1986), Equation(13). 3772 3542 3773 3543 3774 3544 3775 3776 3777 * 3.11. MassSurfaceFractal*3545 .. _MassSurfaceFractal: 3546 3547 **2.2.11. MassSurfaceFractal** 3778 3548 3779 3549 A number of natural and commercial processes form high-surface area … … 3782 3552 fume or pyrogenic silicas. These are all characterised by cluster mass 3783 3553 distributions (sometimes also cluster size distributions) and internal 3784 surfaces that are fractal in nature. The scattering from such3554 surfaces that are fractal in nature.  The scattering from such 3785 3555 materials displays two distinct breaks in log-log representation, 3786 3556 corresponding to the radius-of-gyration of the primary particles, rg, 3787 3557 and 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 theprimary particles, Ds.3792 3793 The scattered intensity I(Q)is then calculated using a modified3558 these boundaries the scattering follows a power law related to the mass 3559 fractal dimension, Dm, whilst above the high-Q boundary the scattering 3560 follows a power law related to the surface fractal dimension of the 3561 primary particles, Ds. 3562 3563 The scattered intensity *I(q)* is then calculated using a modified 3794 3564 Ornstein-Zernicke equation: 3795 3565 3796 3797 3798 3799 3800 3801 3802 3803 3566 .. image:: img/masssurface_fractal_eq1.JPG 3804 3567 3805 3568 The 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 the3807 scattering length density of the solvent, and * p* is the scattering3569 fractal dimension, Dm is the mass fractal dimension, *Ãï¿œsolvent* is the 3570 scattering length density of the solvent, and *Ãï¿œp* is the scattering 3808 3571 length density of particles. 3809 3572 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 3574 0<surface\_dim<6, 0<mass\_dim<6, and (surface\_mass+mass\_dim)<6. 3575 3576 ============== ======== ============= 3577 Parameter 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 3846 3593 3847 3594 *Figure. 1D plot* 3848 3595 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)* 3596 REFERENCE 3597 3598 P. Schmidt, J Appl. Cryst., 24, 414-435 (1991), Equation(19). 3599 3600 Hurd, Schaefer, Martin, Phys. Rev. A, 35, 2361-2364 (1987), Equation(2). 3601 3602 3603 3604 .. _FractalCoreShell: 3605 3606 **2.2.12. FractalCoreShell(Model)** 3865 3607 3866 3608 Calculates the scattering from a fractal structure with a primary 3867 3609 building block of core-shell spheres. 3868 3610 3869 3870 3871 3872 The formfactor P(q) is CoreShellModel with bkg = 0, 3873 , 3611 .. image:: img/fractcore_eq1.GIF 3612 3613 The formfactor P(q) is `CoreShellModel <#CoreShellModel>`__ with bkg 3614 = 0, 3615 3616 .. image:: img/image013.PNG 3874 3617 3875 3618 while the fractal structure factor S(q); 3876 3619 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 3622 where Df = frac\_dim, ß = cor\_length, rc = (core) radius, and scale 3623 = volfraction. 3624 3625 The fractal structure is as documented in the fractal model. This model 3626 could find use for aggregates of coated particles, or aggregates of 3627 vesicles. The polydispersity computation of radius and thickness is 3884 3628 provided. 3885 3629 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 3630 The returned value is scaled to units of |cm^-1|, absolute scale. 3631 3632 See each of these individual models for full documentation. 3633 3634 For 2D plot, the wave transfer is defined as 3635 3636 .. image:: img/image040.GIF 3637 3638 ============== ======== ============= 3639 Parameter 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 | ÃâŠ-2 3.5e-6 3652 3653 | shell\_sld | ÃâŠ-2 1e-6 3654 3655 | solvent\_sld | ÃâŠ-2 6.35e-6 3656 3657 | background | cm-1 0.0 3658 ============== ======== ============= 3659 3660 .. image:: img/image188.JPG 3949 3661 3950 3662 *Figure. 1D plot using the default values (w/500 data points).* 3951 3663 3952 3953 3954 3955 3956 REFERENCE 3957 3958 See the PolyCore and Fractal documentation. * * 3959 3960 * 3.13. GaussLorentzGel(Model)*3664 REFERENCE 3665 3666 See the PolyCore and Fractal documentation.\ 3667 3668 3669 3670 .. _GaussLorentzGel: 3671 3672 **2.2.13. GaussLorentzGel(Model)** 3961 3673 3962 3674 Calculates the scattering from a gel structure, typically a physical … … 3965 3677 structures. 3966 3678 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 the3679 The returned value is scaled to units of |cm^-1|, absolute scale. 3680 3681 The scattering intensity *I(q)* is calculated as (eqn 5 from the 3970 3682 reference): 3971 3683 3972 3973 3974 3684 .. image:: img/image189.JPG 3975 3685 3976 3686 Uppercase Zeta is the static correlations in the gel, which can be 3977 attributed to the "frozen-in" crosslinks of some gels. Lowercase zeta 3978 isthe dynamic correlation length, which can be attributed to the3687 attributed to the "frozen-in" crosslinks of some gels. Lowercase zeta is 3688 the dynamic correlation length, which can be attributed to the 3979 3689 fluctuating polymer chain between crosslinks. IG(0) and IL(0) are the 3980 3690 scaling factors for each of these structures. Your physical system may 3981 3691 be different, so think about the interpretation of these parameters. 3982 3692 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 3693 Note that the peaked structure at higher q values (from Figure 2 of the 3694 reference below) is not reproduced by the model. Peaks can be introduced 3695 into the model by summing this model with the PeakGauss Model function. 3696 3697 For 2D plot, the wave transfer is defined as 3698 3699 .. image:: img/image040.GIF 3700 3701 ============== ======== ============= 3702 Parameter 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 4025 3720 4026 3721 *Figure. 1D plot using the default values (w/500 data points).* 4027 4028 4029 4030 4031 3722 4032 3723 REFERENCE … … 4035 3726 (2001) 2907-2913. 4036 3727 4037 *3.14. BEPolyelectrolyte Model* 3728 3729 3730 .. _BEPolyelectrolyte: 3731 3732 **2.2.14. BEPolyelectrolyte Model** 4038 3733 4039 3734 Calculates 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 3735 RPA expression derived by Borue and Erukhimovich. The value returned is 3736 in cm-1. 3737 3738 .. image:: img/image191.PNG 4048 3739 4049 3740 K is a contrast factor of the polymer, Lb is the Bjerrum length, h is 4050 3741 the virial parameter, b is the monomer length, Cs is the concentration 4051 of monovalent salt, is the ionization degree, Ca is the polymer molar3742 of monovalent salt, ñ is the ionization degree, Ca is the polymer molar 4052 3743 concentration, and background is the incoherent background. 4053 3744 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 3745 For 2D plot, the wave transfer is defined as 3746 3747 .. image:: img/image040.GIF 3748 3749 ============== ======== ============= 3750 Parameter name Units Default value 3751 ============== ======== ============= 3752 | K Barns = 10-24 cm2 | 10 3753 3754 | Lb Ã⊠7.1 3755 3756 | h ÃâŠ-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 ============== ======== ============= 4109 3768 4110 3769 REFERENCE … … 4115 3774 4116 3775 Moussaid, 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)* 3776 Physique II France 3, 573 (1993). 3777 3778 Raphaël, E., Joanny, J.-F., Europhysics Letters 11, 179 (1990). 3779 3780 3781 3782 .. _Guinier: 3783 3784 **2.2.15. Guinier (Model)** 3785 3786 A Guinier analysis is done by linearizing the data at low q by plotting 3787 it as log(I) versus Q2. The Guinier radius Rg can be obtained by fitting 3788 the following model: 3789 3790 .. image:: img/image192.PNG 3791 3792 For 2D plot, the wave transfer is defined as 3793 3794 .. image:: img/image040.GIF 3795 3796 ============== ======== ============= 3797 Parameter name Units Default value 3798 ============== ======== ============= 3799 | scale cm-1 1.0 3800 3801 | Rg Ã⊠0.1 3802 ============== ======== ============= 3803 3804 3805 3806 .. _GuinierPorod: 3807 3808 **2.2.16. GuinierPorod (Model)** 4158 3809 4159 3810 Calculates the scattering for a generalized Guinier/power law object. … … 4162 3813 4163 3814 The 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|,3815 incoherent background term. The result is in the units of |cm^-1|, 4165 3816 absolute scale. 4166 3817 … … 4168 3819 asymmetric objects such as rods or platelets. It also applies to 4169 3820 intermediate 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. 3821 platelets. The following functional form is used: 3822 3823 .. image:: img/image193.JPG  (1) 3824 3825 This 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 3827 the standard Guinier formula. For 2D symmetry (such as for rods) s = 1 3828 and for 1D symmetry (such as for lamellae or platelets) s = 2. A 3829 dimensionality parameter 3-s is defined, and is 3 for spherical objects, 3830 2 for rods, and 1 for plates. 4182 3831 4183 3832 Enforcing the continuity of the Guinier and Porod functions and their 4184 derivatives yields: 4185 4186 3833 derivatives yields: 3834 3835 .. image:: img/image194.JPG 4187 3836 4188 3837 and 4189 3838 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 3841 Note 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 3845 is given by Rg = R / sqrt(2). 3846 3847 The cross section of a randomly oriented lamella of thickness T is given 3848 by Rg = T / sqrt(12). 4202 3849 4203 3850 The intensity given by Eq. 1 is the calculated result, and is plotted … … 4210 3857 4211 3858 [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 * * 3859 Press (1982). Check out Chapter 4 on Data Treatment, pages 155-156. 3860 3861 For 2D plot, the wave transfer is defined as 3862 3863 .. image:: img/image008.PNG 3864 3865 ============== ======== ============= 3866 Parameter name Units Default value 3867 ============== ======== ============= 3868 | Scale(=Guinier scale, | cm-1 1.0 3869 | G) 3870 3871 | rg Ã⊠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 4251 3882 4252 3883 *Figure. 1D plot using the default values (w/500 data points).* … … 4254 3885 4255 3886 4256 4257 4258 * 3.17. PorodModel*3887 .. _PorodModel: 3888 3889 **2.2.17. PorodModel** 4259 3890 4260 3891 A Porod analysis is done by linearizing the data at high q by plotting … … 4262 3893 following model: 4263 3894 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 3897 C is the scale factor and  Sv is the specific surface area of the sample 3898 and ÃâÃï¿œ is the contrast factor. 4270 3899 4271 3900 The background term is added for data analysis. 4272 3901 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* 3902 For 2D plot, the wave transfer is defined as 3903 3904 .. image:: img/image040.GIF 3905 3906 ============== ======== ============= 3907 Parameter name Units Default value 3908 ============== ======== ============= 3909 | scale ÃâŠ-4 0.1 3910 3911 | background | cm-1 0 3912 ============== ======== ============= 3913 3914 3915 3916 .. _PeakGaussModel: 3917 3918 **2.2.18. PeakGaussModel** 4296 3919 4297 3920 Model describes a Gaussian shaped peak including a flat background, 4298 3921 4299 4300 4301 4302 4303 3922 .. image:: img/image198.PNG 4304 3923 4305 3924 with the peak having height of I0 centered at qpk having standard 4306 deviation of B. The fwhm is 2.354*B.3925 deviation of B. The fwhm is 2.354\*B.  4307 3926 4308 3927 Parameters I0, B, qpk, and BGD can all be adjusted during fitting. … … 4310 3929 REFERENCE 4311 3930 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 * * 3931 None 3932 3933 For 2D plot, the wave transfer is defined as 3934 3935 .. image:: img/image040.GIF 3936 3937 ============== ======== ============= 3938 Parameter name Units Default value 3939 ============== ======== ============= 3940 | scale cm-1 100 3941 3942 | q0 Ã⊠0.05 3943 3944 | B  0.005 3945 3946 | background |  1 3947 ============== ======== ============= 3948 3949 .. image:: img/image199.JPG 4349 3950 4350 3951 *Figure. 1D plot using the default values (w/500 data points).* … … 4352 3953 4353 3954 4354 *3.19. PeakLorentzModel* 3955 .. _PeakLorentzModel: 3956 3957 **2.2.19. PeakLorentzModel** 4355 3958 4356 3959 Model describes a Lorentzian shaped peak including a flat background, 4357 3960 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 3963 with the peak having height of I0 centered at qpk having a hwhm 3964 (half-width-half-maximum) of B. 4366 3965 4367 3966 The parameters I0, B, qpk, and BGD can all be adjusted during fitting. … … 4369 3968 REFERENCE 4370 3969 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 3970 None 3971 3972 For 2D plot, the wave transfer is defined as 3973 3974 .. image:: img/image040.GIF 3975 3976 ============== ======== ============= 3977 Parameter name Units Default value 3978 ============== ======== ============= 3979 | scale cm-1 100 3980 3981 | q0 Ã⊠0.05 3982 3983 | B  0.005 3984 3985 | background |  1 3986 ============== ======== ============= 3987 3988 .. image:: img/image201.JPG 4407 3989 4408 3990 *Figure. 1D plot using the default values (w/500 data points).* 4409 3991 4410 *3.20. Poly_GaussCoil (Model)* 3992 3993 3994 .. _Poly_GaussCoil: 3995 3996 **2.2.20. Poly_GaussCoil (Model)** 4411 3997 4412 3998 Polydisperse Gaussian Coil: Calculate an empirical functional form for 4413 3999 scattering from a polydisperse polymer chain ina good solvent. The 4414 4000 polymer 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 4001 molecular weight distribution. 4002 4003 The returned value is scaled to units of |cm^-1|, absolute scale. 4004 4005 .. image:: img/image202.PNG 4420 4006 4421 4007 where the dimensionless chain dimension is: 4422 4008 4423 4009 .. image:: img/image203.PNG 4424 4010 4425 4011 and the polydispersion is 4426 4012 4427 . 4428 4429 The scattering intensity I(q)is calculated as:4013 .. image:: img/image204.PNG 4014 4015 The scattering intensity *I(q)* is calculated as: 4430 4016 4431 4017 The polydispersion in rg is provided. 4432 4018 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 4019 For 2D plot, the wave transfer is defined as 4020 4021 .. image:: img/image040.GIF 4022 4023 TEST DATASET 4024 4025  This example dataset is produced by running the Poly\_GaussCoil, using 4026 200 data points, qmin = 0.001 ÃâŠ-1, qmax = 0.7 ÃâŠ-1  and the default 4027 values below. 4028 4029 ============== ======== ============= 4030 Parameter name Units Default value 4031 ============== ======== ============= 4032 | Scale None 1.0 4033 4034 | rg Ã⊠60.0 4035 4036 | poly\_m Mw/Mn 2 4037 4038 | background | cm-1 0.001 4039 ============== ======== ============= 4040 4041 .. image:: img/image205.JPG 4476 4042 4477 4043 *Figure. 1D plot using the default values (w/200 data point).* 4478 4044 4479 4480 4481 4045 REFERENCE 4482 4046 4483 4047 Glatter & Kratky - pg.404. 4484 4048 4485 J.S. Higgins, and H.C. Benoit, Polymers and Neutron Scattering, Oxford Science Publications (1996). 4486 4487 *3.21. PolymerExclVolume (Model)* 4049 J.S. Higgins, and H.C. Benoit, Polymers and Neutron Scattering, Oxford 4050 Science Publications (1996). 4051 4052 4053 4054 .. _PolyExclVolume: 4055 4056 **2.2.21. PolymerExclVolume (Model)** 4488 4057 4489 4058 Calculates the scattering from polymers with excluded volume effects. 4490 4059 4491 The returned value is scaled to units of |cm^-1| \ |sr^-1|, absolute scale.4060 The returned value is scaled to units of |cm^-1|, absolute scale. 4492 4061 4493 4062 The 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|,4063 incoherent background term. The result is in the units of |cm^-1|, 4495 4064 absolute scale. 4496 4065 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 factor4500 for that model (Benoit, 1957) was originally presented in the 4501 followingintegral form:4502 4503 (1)4066 A model describing polymer chain conformations with excluded volume was 4067 introduced to describe the conformation of polymer chains, and has been 4068 used as a template for describing mass fractals. The form factor for 4069 that model (Benoit, 1957) was originally presented in the following 4070 integral form: 4071 4072 .. image:: img/image206.JPG    (1) 4504 4073 4505 4074 Here 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 intoan almost analytical form (Hammouda, 1993) as follows:4509 4510 (2)4075 exponent m as n = 1/m, a is the polymer chain statistical segment length 4076 and n is the degree of polymerization. This integral was later put into 4077 an almost analytical form (Hammouda, 1993) as follows: 4078 4079 .. image:: img/image207.JPG   (2) 4511 4080 4512 4081 Here, g(x,U) is the incomplete gamma function which is a built-in 4513 4082 function in computer libraries. 4514 4083 4515 4084 .. image:: img/image208.JPG 4516 4085 4517 4086 The variable U is given in terms of the scattering variable Q as: 4518 4087 4519 4088 .. image:: img/image209.JPG 4520 4089 4521 4090 The radius of gyration squared has been defined as: 4522 4091 4523 4092 .. image:: img/image210.JPG 4524 4093 4525 4094 Note that this model describing polymer chains with excluded volume 4526 4095 applies 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). 4096 apply to surface fractals ( 3 < m <= 4). It does not reproduce the rigid 4097 rod limit (m = 1) because it assumes chain flexibility from the outset. 4098 It may cover a portion of the semiflexible chain range ( 1 < m < 5/3). 4531 4099 4532 4100 The low-Q expansion yields the Guinier form and the high-Q expansion 4533 4101 yields the Porod form which is given by: 4534 4102 4535 4103 .. image:: img/image211.JPG 4536 4104 4537 4105 Here G(x) = g(x,inf) is the gamma function. The asymptotic limit is 4538 4106 dominated by the first term: 4539 4107 4540 4108 .. image:: img/image212.JPG 4541 4109 4542 4110 The special case when n = 0.5 (or m = 1/n = 2) corresponds to Gaussian … … 4544 4112 function. 4545 4113 4546 4547 4548 The form factor given by Eq. 2 is the calculated result, and is 4549 plottedbelow for the default parameter values.4114 .. image:: img/image213.JPG 4115 4116 The form factor given by Eq. 2 is the calculated result, and is plotted 4117 below for the default parameter values. 4550 4118 4551 4119 REFERENCE … … 4553 4121 Benoit, H., Comptes Rendus (1957). 245, 2244-2247. 4554 4122 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 4123 Hammouda, B., SANS from Homogeneous Polymer Mixtures  A Unified 4124 Overview, Advances in Polym. Sci. (1993), 106, 87-133. 4125 4126 For 2D plot, the wave transfer is defined as 4127 4128 .. image:: img/image040.GIF 4129 4130 TEST DATASET 4131 4132  This example dataset is produced, using 200 data points, qmin = 0.001 4133 ÃâŠ-1, qmax = 0.2 ÃâŠ-1  and the default values below. 4134 4135 ============== ======== ============= 4136 Parameter name Units Default value 4137 ============== ======== ============= 4138 | Scale None 1.0 4139 4140 | rg Ã⊠60.0 4141 4142 | m(=Porod exponent) |  3 4143 4144 | background | cm-1 0.0 4145 ============== ======== ============= 4146 4147 .. image:: img/image214.JPG 4595 4148 4596 4149 *Figure. 1D plot using the default values (w/500 data points).* … … 4598 4151 4599 4152 4600 *3.22. RPA10Model* 4153 .. _RPA10Model: 4154 4155 **2.2.22. RPA10Model** 4601 4156 4602 4157 Calculates the macroscopic scattering intensity (units of cm^-1) for a … … 4624 4179 Case 9: A-B-C-D Four-block copolymer 4625 4180 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 4181 Note: the case numbers are different from the IGOR/NIST SANS package. 4182 4183 Only one case can be used at any one time. Plotting a different case 4631 4184 will overwrite the original parameter waves. 4632 4185 4633 The returned value is scaled to units of |cm^-1|.4186 The returned value is scaled to units of [cm-1]. 4634 4187 4635 4188 Component D is assumed to be the "background" component (all contrasts 4636 4189 are calculated with respect to component D). 4637 4190 4638 Scattering contrast for a C/D blend= {SLD (component C) - SLD 4639 (componentD)}24640 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 heldconstant equal to unity.4191 Scattering contrast for a C/D blend= {SLD (component C) - SLD (component 4192 D)}2 4193 4194 Depending on what case is used, the number of fitting parameters varies. 4195 These 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 4197 constant equal to unity. 4645 4198 4646 4199 The input parameters are the degree of polymerization, the volume … … 4655 4208 A.Z. Akcasu, R. Klein and B. Hammouda, Macromolecules 26, 4136 (1993) 4656 4209 4657 4658 4659 4210 Fitting parameters for Case0 Model 4660 4211 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 ============== ======== ============= 4213 Parameter 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 ============== ======== ============= 4692 4225 4693 4226 Fixed parameters for Case0 Model 4694 4227 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 ============== ======== ============= 4229 Parameter 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 4738 4253 4739 4254 *Figure. 1D plot using the default values (w/500 data points).* … … 4741 4256 4742 4257 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 4263 Calculate an empirical functional form for SANS data characterized by a 4264 two Lorentzian functions. 4265 4266 The returned value is scaled to units of |cm^-1|, absolute scale. 4267 4268 The scattering intensity *I(q)* is calculated by: 4269 4270 .. image:: img/image216.JPG 4755 4271 4756 4272 A = Lorentzian scale #1 4757 4273 4758 C = Lorentzian scale #2 4274 C = Lorentzian scale #2 4759 4275 4760 4276 where scale is the peak height centered at q0, and B refers to the … … 4763 4279 The background term is added for data analysis. 4764 4280 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 4281 For 2D plot, the wave transfer is defined as 4282 4283 .. image:: img/image040.GIF 4284 4285 **Default input parameter values** 4286 4287 ============== ======== ============= 4288 Parameter 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 4814 4308 4815 4309 *Figure. 1D plot using the default values (w/500 data points).* 4816 4310 4817 4818 4819 REFERENCE 4820 4821 *None* 4822 4823 *3.24. TwoPowerLaw(Model)* 4311 REFERENCE 4312 4313 None 4314 4315 4316 4317 .. _TwoPowerLaw: 4318 4319 **2.2.24. TwoPowerLaw(Model)** 4824 4320 4825 4321 Calculate an empirical functional form for SANS data characterized by 4826 4322 two power laws. 4827 4323 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 4324 The returned value is scaled to units of |cm^-1|, absolute scale. 4325 4326 The scattering intensity *I(q)* is calculated by: 4327 4328 .. image:: img/image218.JPG 4837 4329 4838 4330 qc is the location of the crossover from one slope to the other. The 4839 4331 scaling 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 4332 The scaling of the second power law region is scaled to match the first. 4333 Be sure to enter the power law exponents as positive values. 4334 4335 For 2D plot, the wave transfer is defined as 4336 4337 .. image:: img/image040.GIF 4338 4339 **Default input parameter values** 4340 4341 ============== ======== ============= 4342 Parameter name Units Default value 4343 ============== ======== ============= 4344 | coef\_A  1.0 4345 4346 | qc ÃâŠ-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 4882 4356 4883 4357 *Figure. 1D plot using the default values (w/500 data points).* … … 4885 4359 4886 4360 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 4365 The returned value is scaled to units of |cm^-1|, absolute scale. 4366 4367 Note that the level 0 is an extra function that is the inverse function; 4368 I (q) = scale/q + background. 4893 4369 4894 4370 Otherwise, program incorporates the empirical multiple level unified … … 4899 4375 The empirical expressions are able to reasonably approximate the 4900 4376 scattering 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. 4377 clusters, random coils (Debye equation), ellipsoidal particles, etc. 4378 The empirical fit function is 4379 4380 .. image:: img/image220.JPG 4381 4382 For each level, the four parameters Gi, Rg,i, Bi and Pi must be chosen. 4910 4383 4911 4384 For 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 4385 equation), set Rg,i as the Guinier radius, Pi = 2, and Bi = 2 Gi / Rg,i 4914 4386 4915 4387 See the listed references for further information on choosing the 4916 4388 parameters. 4917 4389 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 4390 For 2D plot, the wave transfer is defined as 4391 4392 .. image:: img/image040.GIF 4393 4394 **Default input parameter values** 4395 4396 ============== ======== ============= 4397 Parameter 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 4989 4421 4990 4422 *Figure. 1D plot using the default values (w/500 data points).* 4991 4423 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* 4424 REFERENCE 4425 4426 G. Beaucage (1995). J. Appl. Cryst., vol. 28, p717-728. 4427 4428 G. Beaucage (1996). J. Appl. Cryst., vol. 29, p134-146. 4429 4430 4431 4432 .. _LineModel: 4433 4434 **2.2.26. LineModel** 5001 4435 5002 4436 This is a linear function that calculates: 5003 4437 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 4440 where 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 5012 4443 from other shape independent models. 5013 4444 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 ============== ======== ============= 4446 Parameter 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** 5035 4458 5036 4459 This model calculates the reflectivity and uses the Parrett algorithm. 5037 4460 Up to nine film layers are supported between Bottom(substrate) and 5038 4461 Medium(Superstrate where the neutron enters the first top film). Each 5039 layers are composed of [ of the interface(from the previous layer or5040 substrate) + flat portion + of the interface(to the next layer or4462 layers are composed of [ Âœ of the interface(from the previous layer or 4463 substrate) + flat portion + Âœ of the interface(to the next layer or 5041 4464 medium)]. Only two simple interfacial functions are selectable, error 5042 4465 function and linear function. The each interfacial thickness is … … 5044 4467 sigma=roughness). 5045 4468 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 4469 Note: 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)* 4474 http://www.ncnr.nist.gov/resources/reflcalc.html 4475 4476 .. image:: img/image232.GIF 5055 4477 5056 4478 *Figure. SLD profile used for the calculation(above).* 5057 4479 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 4487 customizable. More interfacial functions are supplied. The number of 4488 points (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 4490 power-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 4492 functions are: 5066 4493 5067 4494 1) Erf; 5068 4495 5069 4496 .. image:: img/image051.GIF 5070 4497 5071 4498 2) Power-Law; 5072 4499 5073 5074 5075 5076 5077 4500 .. image:: img/image050.GIF 5078 4501 5079 4502 3) Exp; 5080 4503 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 5090 4515 distribution in a gel involves at least two characteristic length 5091 4516 scales, a shorter correlation length (a1) to describe the rapid 5092 4517 fluctuations in the position of the polymer chains that ensure 5093 4518 thermodynamic 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 asimple Guinier function.5097 5098 The scattered intensity I(Q)is then calculated as:5099 5100 4519 needed to account for the static accumulations of polymer pinned down by 4520 junction points or clusters of such points. The letter is derived from a 4521 simple Guinier function. 4522 4523 The scattered intensity *I(q)* is then calculated as: 4524 4525 .. image:: img/image233.GIF 5101 4526 5102 4527 Where: 5103 4528 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 4532 D=2; ie, when the Flory exponent is 0.5 (theta conditions).  In gels 4533 with 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 ============== ======== ============= 4540 Parameter 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 5164 4556 5165 4557 *Figure. 1D plot using the default values (w/300 data points, 5166 *qmin*=0.001, and *qmax*=0.3).* 5167 5168 4558 qmin=0.001, and qmax=0.3).* 5169 4559 5170 4560 REFERENCE … … 5178 4568 5179 4569 5180 **3.30. Star Polymer with Gaussian Statistics** 4570 .. _StarPolymer: 4571 4572 **2.2.30. Star Polymer with Gaussian Statistics** 5181 4573 5182 4574 For a star with *f* arms: 5183 4575 5184 5185 5186 5187 5188 4576 .. image:: img/star1.PNG 4577 4578 .. image:: img/star2.PNG 4579 4580 .. image:: img/star3.PNG 5189 4581 5190 4582 where is the ensemble average radius of gyration squared of an arm. 5191 4583 5192 5193 5194 REFERENCE 5195 5196 H. Benoit, J. Polymer Science., 11, 596-599 (1953) 5197 5198 5199 4584 REFERENCE 4585 4586 H. Benoit,  J. Polymer Science., 11, 596-599 (1953) 5200 4587 5201 4588
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