Changeset d4117ccb in sasview for src/sans/models/media


Ignore:
Timestamp:
Apr 16, 2014 3:00:07 AM (11 years ago)
Author:
smk78
Branches:
master, ESS_GUI, ESS_GUI_Docs, ESS_GUI_batch_fitting, ESS_GUI_bumps_abstraction, ESS_GUI_iss1116, ESS_GUI_iss879, ESS_GUI_iss959, ESS_GUI_opencl, ESS_GUI_ordering, ESS_GUI_sync_sascalc, costrafo411, magnetic_scatt, release-4.1.1, release-4.1.2, release-4.2.2, release_4.0.1, ticket-1009, ticket-1094-headless, ticket-1242-2d-resolution, ticket-1243, ticket-1249, ticket885, unittest-saveload
Children:
2e3b055
Parents:
1127c32
Message:

More updates by SMK

File:
1 edited

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  • src/sans/models/media/model_functions.rst

    r1127c32 rd4117ccb  
    195195 
    196196- LamellarPCrystalModel_ 
    197 - SCCrystalModel 
    198 - FCCrystalModel 
    199 - BCCrystalModel 
     197- SCCrystalModel_ 
     198- FCCrystalModel_ 
     199- BCCrystalModel_ 
    200200 
    201201Parallelpipeds 
     
    26132613 
    26142614Here, the scale factor is used instead of the mass per area of the bilayer (*G*). The scale factor is the volume 
    2615 fraction of the material in the bilayer, *not* the total excluded volume of the paracrystal. *ZN(q)* describes the 
    2616 interference effects for aggregates consisting of more than one bilayer. The equations used are (3-5) from the 
    2617 Bergstrom reference below. 
     2615fraction of the material in the bilayer, *not* the total excluded volume of the paracrystal. *Z*\ :sub:`N`\ *(q)* 
     2616describes the interference effects for aggregates consisting of more than one bilayer. The equations used are (3-5) 
     2617from the Bergstrom reference below. 
    26182618 
    26192619Non-integer numbers of stacks are calculated as a linear combination of the lower and higher values 
     
    26572657**2.1.34. SCCrystalModel** 
    26582658 
    2659 Calculates the scattering from a simple cubic lattice with 
    2660 paracrystalline distortion. Thermal vibrations are considered to be 
    2661 negligible, and the size of the paracrystal is infinitely large. 
    2662 Paracrystalline distortion is assumed to be isotropic and 
    2663 characterized by a Gaussian distribution. 
     2659Calculates the scattering from a **simple cubic lattice** with paracrystalline distortion. Thermal vibrations are 
     2660considered to be negligible, and the size of the paracrystal is infinitely large. Paracrystalline distortion is assumed 
     2661to be isotropic and characterized by a Gaussian distribution. 
    26642662 
    26652663The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    26662664 
     2665*2.1.34.1. Definition* 
     2666 
    26672667The scattering intensity I(q) is calculated as 
    26682668 
    2669  
    2670  
    2671 where scale is the volume fraction of spheres, Vp is the volume of the 
    2672 primary particle, V(lattice) is a volume correction for the crystal 
    2673 structure, P(q) is the form factor of the sphere (normalized) and Z(q) 
    2674 is the paracrystalline structure factor for a simple cubic structure. 
    2675 Equation (16) of the 1987 reference is used to calculate Z(q), using 
    2676 equations (13)-(15) from the 1987 paper for Z1, Z2, and Z3. 
    2677  
    2678 The lattice correction (the occupied volume of the lattice) for a 
    2679 simple cubic structure of particles of radius R and nearest neighbor 
    2680 separation D is: 
    2681  
    2682  
    2683  
    2684 The distortion factor (one standard deviation) of the paracrystal is 
    2685 included in the calculation of Z(q): 
    2686  
    2687  
    2688  
    2689 where g is a fractional distortion based on the nearest neighbor 
    2690 distance. 
    2691  
    2692 The simple cubic lattice is: 
    2693  
    2694  
    2695  
    2696 For a crystal, diffraction peaks appear at reduced q-values givn by: 
    2697  
    2698  
    2699  
    2700 where for a simple cubic lattice any h, k, l are allowed and none are 
    2701 forbidden. Thus the peak positions correspond to (just the first 5): 
    2702  
    2703  
    2704  
    2705 NB: The calculation of Z(q) is a double numerical integral that must 
    2706 be carried out with a high density of points to properly capture the 
    2707 sharp peaks of the paracrystalline scattering. So be warned that the 
    2708 calculation is SLOW. Go get some coffee. Fitting of any experimental 
    2709 data must be resolution smeared for any meaningful fit. This makes a 
    2710 triple integral. Very, very slow. Go get lunch. 
    2711  
    2712 REFERENCE 
    2713  
    2714 Hideki Matsuoka et. al. *Physical Review B*, 36 (1987) 1754-1765 
    2715 (Original Paper) 
    2716  
    2717 Hideki Matsuoka et. al. *Physical Review B*, 41 (1990) 3854 -3856 
    2718 (Corrections to FCC and BCC lattice structure calculation) 
     2669.. image:: img/image149.JPG 
     2670 
     2671where *scale* is the volume fraction of spheres, *Vp* is the volume of the primary particle, *V(lattice)* is a volume 
     2672correction for the crystal structure, *P(q)* is the form factor of the sphere (normalized), and *Z(q)* is the 
     2673paracrystalline structure factor for a simple cubic structure. 
     2674 
     2675Equation (16) of the 1987 reference is used to calculate *Z(q)*, using equations (13)-(15) from the 1987 paper for 
     2676*Z1*\ , *Z2*\ , and *Z3*\ . 
     2677 
     2678The lattice correction (the occupied volume of the lattice) for a simple cubic structure of particles of radius *R* 
     2679and nearest neighbor separation *D* is 
     2680 
     2681.. image:: img/image150.JPG 
     2682 
     2683The distortion factor (one standard deviation) of the paracrystal is included in the calculation of *Z(q)* 
     2684 
     2685.. image:: img/image151.JPG 
     2686 
     2687where *g* is a fractional distortion based on the nearest neighbor distance. 
     2688 
     2689The simple cubic lattice is 
     2690 
     2691.. image:: img/image152.JPG 
     2692 
     2693For a crystal, diffraction peaks appear at reduced *q*\ -values given by 
     2694 
     2695.. image:: img/image153.JPG 
     2696 
     2697where for a simple cubic lattice any *h*\ , *k*\ , *l* are allowed and none are forbidden. Thus the peak positions 
     2698correspond to (just the first 5) 
     2699 
     2700.. image:: img/image154.JPG 
     2701 
     2702**NB: The calculation of** *Z(q)* **is a double numerical integral that must be carried out with a high density of** 
     2703**points to properly capture the sharp peaks of the paracrystalline scattering.** So be warned that the calculation is 
     2704SLOW. Go get some coffee. Fitting of any experimental data must be resolution smeared for any meaningful fit. This 
     2705makes a triple integral. Very, very slow. Go get lunch! 
    27192706 
    27202707==============  ========  ============= 
     
    27302717==============  ========  ============= 
    27312718 
    2732  
    2733  
    2734 This example dataset is produced using 200 data points, *qmin* = 0.01 
    2735 -1, *qmax* = 0.1 -1 and the above default values. 
    2736  
    2737  
    2738  
    2739 *Figure. 1D plot in the linear scale using the default values (w/200 
    2740 data point).* 
    2741  
    2742 The 2D (Anisotropic model) is based on the reference (above) which 
    2743 I(q) is approximated for 1d scattering. Thus the scattering pattern 
    2744 for 2D may not be accurate. Note that we are not responsible for any 
    2745 incorrectness of the 2D model computation. 
    2746  
    2747  
    2748  
    2749  
    2750  
    2751  
    2752  
    2753  
    2754  
    2755  
    2756  
    2757 * * 
     2719This example dataset is produced using 200 data points, *qmin* = 0.01 |Ang^-1|, *qmax* = 0.1 |Ang^-1| and the above 
     2720default values. 
     2721 
     2722.. image:: img/image155.JPG 
     2723 
     2724*Figure. 1D plot in the linear scale using the default values (w/200 data point).* 
     2725 
     2726The 2D (Anisotropic model) is based on the reference below where *I(q)* is approximated for 1d scattering. Thus the 
     2727scattering pattern for 2D may not be accurate. Note that we are not responsible for any incorrectness of the 2D model 
     2728computation. 
     2729 
     2730.. image:: img/image156.JPG 
     2731 
     2732.. image:: img/image157.JPG 
    27582733 
    27592734*Figure. 2D plot using the default values (w/200X200 pixels).* 
    2760  
    2761  
    2762  
    2763 .. _FCCrystalModel: 
    2764  
    2765 **2.1.35. FCCrystalModel** 
    2766  
    2767 Calculates the scattering from a face-centered cubic lattice with 
    2768 paracrystalline distortion. Thermal vibrations are considered to be 
    2769 negligible, and the size of the paracrystal is infinitely large. 
    2770 Paracrystalline distortion is assumed to be isotropic and 
    2771 characterized by a Gaussian distribution. 
    2772  
    2773 The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
    2774  
    2775 The scattering intensity I(q) is calculated as: 
    2776  
    2777  
    2778  
    2779 where scale is the volume fraction of spheres, Vp is the volume of the 
    2780 primary particle, V(lattice) is a volume correction for the crystal 
    2781 structure, P(q) is the form factor of the sphere (normalized) and Z(q) 
    2782 is the paracrystalline structure factor for a face-centered cubic 
    2783 structure. Equation (1) of the 1990 reference is used to calculate 
    2784 Z(q), using equations (23)-(25) from the 1987 paper for Z1, Z2, and 
    2785 Z3. 
    2786  
    2787 The lattice correction (the occupied volume of the lattice) for a 
    2788 face-centered cubic structure of particles of radius R and nearest 
    2789 neighbor separation D is: 
    2790  
    2791  
    2792  
    2793 The distortion factor (one standard deviation) of the paracrystal is 
    2794 included in the calculation of Z(q): 
    2795  
    2796  
    2797  
    2798 where g is a fractional distortion based on the nearest neighbor 
    2799 distance. 
    2800  
    2801 The face-centered cubic lattice is: 
    2802  
    2803  
    2804  
    2805 For a crystal, diffraction peaks appear at reduced q-values givn by: 
    2806  
    2807  
    2808  
    2809 where for a face-centered cubic lattice h, k, l all odd or all even 
    2810 are allowed and reflections where h, k, l are mixed odd/even are 
    2811 forbidden. Thus the peak positions correspond to (just the first 5): 
    2812  
    2813  
    2814  
    2815 NB: The calculation of Z(q) is a double numerical integral that must 
    2816 be carried out with a high density of points to properly capture the 
    2817 sharp peaks of the paracrystalline scattering. So be warned that the 
    2818 calculation is SLOW. Go get some coffee. Fitting of any experimental 
    2819 data must be resolution smeared for any meaningful fit. This makes a 
    2820 triple integral. Very, very slow. Go get lunch. 
    28212735 
    28222736REFERENCE 
     
    28272741Hideki Matsuoka et. al. *Physical Review B*, 41 (1990) 3854 -3856 
    28282742(Corrections to FCC and BCC lattice structure calculation) 
     2743 
     2744 
     2745 
     2746.. _FCCrystalModel: 
     2747 
     2748**2.1.35. FCCrystalModel** 
     2749 
     2750Calculates the scattering from a **face-centered cubic lattice** with paracrystalline distortion. Thermal vibrations 
     2751are considered to be negligible, and the size of the paracrystal is infinitely large. Paracrystalline distortion is 
     2752assumed to be isotropic and characterized by a Gaussian distribution. 
     2753 
     2754The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
     2755 
     2756*2.1.35.1. Definition* 
     2757 
     2758The scattering intensity *I(q)* is calculated as 
     2759 
     2760.. image:: img/image158.JPG 
     2761 
     2762where *scale* is the volume fraction of spheres, *Vp* is the volume of the primary particle, *V(lattice)* is a volume 
     2763correction for the crystal structure, *P(q)* is the form factor of the sphere (normalized), and *Z(q)* is the 
     2764paracrystalline structure factor for a face-centered cubic structure. 
     2765 
     2766Equation (1) of the 1990 reference is used to calculate *Z(q)*, using equations (23)-(25) from the 1987 paper for 
     2767*Z1*\ , *Z2*\ , and *Z3*\ . 
     2768 
     2769The lattice correction (the occupied volume of the lattice) for a face-centered cubic structure of particles of radius 
     2770*R* and nearest neighbor separation *D* is 
     2771 
     2772.. image:: img/image159.JPG 
     2773 
     2774The distortion factor (one standard deviation) of the paracrystal is included in the calculation of *Z(q)* 
     2775 
     2776.. image:: img/image160.JPG 
     2777 
     2778where *g* is a fractional distortion based on the nearest neighbor distance. 
     2779 
     2780The face-centered cubic lattice is 
     2781 
     2782.. image:: img/image161.JPG 
     2783 
     2784For a crystal, diffraction peaks appear at reduced q-values given by 
     2785 
     2786.. image:: img/image162.JPG 
     2787 
     2788where for a face-centered cubic lattice *h*\ , *k*\ , *l* all odd or all even are allowed and reflections where 
     2789*h*\ , *k*\ , *l* are mixed odd/even are forbidden. Thus the peak positions correspond to (just the first 5) 
     2790 
     2791.. image:: img/image163.JPG 
     2792 
     2793**NB: The calculation of** *Z(q)* **is a double numerical integral that must be carried out with a high density of** 
     2794**points to properly capture the sharp peaks of the paracrystalline scattering.** So be warned that the calculation is 
     2795SLOW. Go get some coffee. Fitting of any experimental data must be resolution smeared for any meaningful fit. This 
     2796makes a triple integral. Very, very slow. Go get lunch! 
    28292797 
    28302798==============  ========  ============= 
     
    28402808==============  ========  ============= 
    28412809 
    2842 This example dataset is produced using 200 data points, *qmin* = 0.01 
    2843 -1, *qmax* = 0.1 -1 and the above default values. 
    2844  
    2845  
    2846  
    2847 *Figure. 1D plot in the linear scale using the default values (w/200 
    2848 data point).* 
    2849  
    2850 The 2D (Anisotropic model) is based on the reference (above) in which 
    2851 I(q) is approximated for 1d scattering. Thus the scattering pattern 
    2852 for 2D may not be accurate. Note that we are not responsible for any 
    2853 incorrectness of the 2D model computation. 
    2854  
     2810This example dataset is produced using 200 data points, *qmin* = 0.01 |Ang^-1|, *qmax* = 0.1 |Ang^-1| and the above 
     2811default values. 
     2812 
     2813.. image:: img/image164.JPG 
     2814 
     2815*Figure. 1D plot in the linear scale using the default values (w/200 data point).* 
     2816 
     2817The 2D (Anisotropic model) is based on the reference below where *I(q)* is approximated for 1d scattering. Thus the 
     2818scattering pattern for 2D may not be accurate. Note that we are not responsible for any incorrectness of the 2D model 
     2819computation. 
     2820 
     2821.. image:: img/image165.GIF 
     2822 
     2823.. image:: img/image166.JPG 
    28552824 
    28562825*Figure. 2D plot using the default values (w/200X200 pixels).* 
    2857  
    2858  
    2859  
    2860 .. _BCCrystalModel: 
    2861  
    2862 **2.1.36. BCCrystalModel** 
    2863  
    2864 Calculates the scattering from a body-centered cubic lattice with 
    2865 paracrystalline distortion. Thermal vibrations are considered to be 
    2866 negligible, and the size of the paracrystal is infinitely large. 
    2867 Paracrystalline distortion is assumed to be isotropic and 
    2868 characterized by a Gaussian distribution.The returned value is scaled 
    2869 to units of |cm^-1|\ |sr^-1|, absolute scale. 
    2870  
    2871 The scattering intensity I(q) is calculated as: 
    2872  
    2873  
    2874  
    2875 where scale is the volume fraction of spheres, Vp is the volume of the 
    2876 primary particle, V(lattice) is a volume correction for the crystal 
    2877 structure, P(q) is the form factor of the sphere (normalized) and Z(q) 
    2878 is the paracrystalline structure factor for a body-centered cubic 
    2879 structure. Equation (1) of the 1990 reference is used to calculate 
    2880 Z(q), using equations (29)-(31) from the 1987 paper for Z1, Z2, and 
    2881 Z3. 
    2882  
    2883 The lattice correction (the occupied volume of the lattice) for a 
    2884 body-centered cubic structure of particles of radius R and nearest 
    2885 neighbor separation D is: 
    2886  
    2887  
    2888  
    2889 The distortion factor (one standard deviation) of the paracrystal is 
    2890 included in the calculation of Z(q): 
    2891  
    2892  
    2893  
    2894 where g is a fractional distortion based on the nearest neighbor 
    2895 distance. 
    2896  
    2897 The body-centered cubic lattice is: 
    2898  
    2899  
    2900  
    2901 For a crystal, diffraction peaks appear at reduced q-values givn by: 
    2902  
    2903  
    2904  
    2905 where for a body-centered cubic lattice, only reflections where 
    2906 (h+k+l) = even are allowed and reflections where (h+k+l) = odd are 
    2907 forbidden. Thus the peak positions correspond to (just the first 5): 
    2908  
    2909  
    2910  
    2911 NB: The calculation of Z(q) is a double numerical integral that must 
    2912 be carried out with a high density of points to properly capture the 
    2913 sharp peaks of the paracrystalline scattering. So be warned that the 
    2914 calculation is SLOW. Go get some coffee. Fitting of any experimental 
    2915 data must be resolution smeared for any meaningful fit. This makes a 
    2916 triple integral. Very, very slow. Go get lunch. 
    29172826 
    29182827REFERENCE 
     
    29232832Hideki Matsuoka et. al. *Physical Review B*, 41 (1990) 3854 -3856 
    29242833(Corrections to FCC and BCC lattice structure calculation) 
     2834 
     2835 
     2836 
     2837.. _BCCrystalModel: 
     2838 
     2839**2.1.36. BCCrystalModel** 
     2840 
     2841Calculates the scattering from a **body-centered cubic lattice** with paracrystalline distortion. Thermal vibrations 
     2842are considered to be negligible, and the size of the paracrystal is infinitely large. Paracrystalline distortion is 
     2843assumed to be isotropic and characterized by a Gaussian distribution. 
     2844 
     2845The returned value is scaled to units of |cm^-1|\ |sr^-1|, absolute scale. 
     2846 
     2847*2.1.36.1. Definition** 
     2848 
     2849The scattering intensity *I(q)* is calculated as 
     2850 
     2851.. image:: img/image167.JPG 
     2852 
     2853where *scale* is the volume fraction of spheres, *Vp* is the volume of the primary particle, *V(lattice)* is a volume 
     2854correction for the crystal structure, *P(q)* is the form factor of the sphere (normalized), and *Z(q)* is the 
     2855paracrystalline structure factor for a body-centered cubic structure. 
     2856 
     2857Equation (1) of the 1990 reference is used to calculate *Z(q)*, using equations (29)-(31) from the 1987 paper for 
     2858*Z1*\ , *Z2*\ , and *Z3*\ . 
     2859 
     2860The lattice correction (the occupied volume of the lattice) for a body-centered cubic structure of particles of radius 
     2861*R* and nearest neighbor separation *D* is 
     2862 
     2863.. image:: img/image159.JPG 
     2864 
     2865The distortion factor (one standard deviation) of the paracrystal is included in the calculation of *Z(q)* 
     2866 
     2867.. image:: img/image160.JPG 
     2868 
     2869where *g* is a fractional distortion based on the nearest neighbor distance. 
     2870 
     2871The body-centered cubic lattice is 
     2872 
     2873.. image:: img/image168.JPG 
     2874 
     2875For a crystal, diffraction peaks appear at reduced q-values given by 
     2876 
     2877.. image:: img/image162.JPG 
     2878 
     2879where for a body-centered cubic lattice, only reflections where (\ *h* + *k* + *l*\ ) = even are allowed and 
     2880reflections where (\ *h* + *k* + *l*\ ) = odd are forbidden. Thus the peak positions correspond to (just the first 5) 
     2881 
     2882.. image:: img/image169.JPG 
     2883 
     2884**NB: The calculation of** *Z(q)* **is a double numerical integral that must be carried out with a high density of** 
     2885**points to properly capture the sharp peaks of the paracrystalline scattering.** So be warned that the calculation is 
     2886SLOW. Go get some coffee. Fitting of any experimental data must be resolution smeared for any meaningful fit. This 
     2887makes a triple integral. Very, very slow. Go get lunch! 
    29252888 
    29262889==============  ========  ============= 
     
    29362899==============  ========  ============= 
    29372900 
    2938  
    2939  
    2940 This example dataset is produced using 200 data points, *qmin* = 0.001 
    2941 -1, *qmax* = 0.1 -1 and the above default values. 
    2942  
    2943  
    2944  
    2945 *Figure. 1D plot in the linear scale using the default values (w/200 
    2946 data point).* 
    2947  
    2948 The 2D (Anisotropic model) is based on the reference (1987) in which 
    2949 I(q) is approximated for 1d scattering. Thus the scattering pattern 
    2950 for 2D may not be accurate. Note that we are not responsible for any 
    2951 incorrectness of the 2D model computation. 
    2952  
    2953  
    2954  
    2955  
    2956  
    2957  
    2958  
    2959  
    2960  
    2961  
    2962  
    2963  
     2901This example dataset is produced using 200 data points, *qmin* = 0.001 |Ang^-1|, *qmax* = 0.1 |Ang^-1| and the above 
     2902default values. 
     2903 
     2904.. image:: img/image170.JPG 
     2905 
     2906*Figure. 1D plot in the linear scale using the default values (w/200 data point).* 
     2907 
     2908The 2D (Anisotropic model) is based on the reference below where *I(q)* is approximated for 1d scattering. Thus the 
     2909scattering pattern for 2D may not be accurate. Note that we are not responsible for any incorrectness of the 2D model 
     2910computation. 
     2911 
     2912.. image:: img/image165.GIF 
     2913 
     2914.. image:: img/image171.JPG 
    29642915 
    29652916*Figure. 2D plot using the default values (w/200X200 pixels).* 
     2917 
     2918REFERENCE 
     2919 
     2920Hideki Matsuoka et. al. *Physical Review B*, 36 (1987) 1754-1765 
     2921(Original Paper) 
     2922 
     2923Hideki Matsuoka et. al. *Physical Review B*, 41 (1990) 3854 -3856 
     2924(Corrections to FCC and BCC lattice structure calculation) 
    29662925 
    29672926 
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