[group] [Superpositional] 4 [Algorithm] -1 -1 -1 -1 -1 -1 -1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 17 16 Form Structure [name] pq---sphere---sq---hayter-penfold-msa [number parameters] 15, [description]

v. 2021-02-24

Form Factor :: Sphere (PQ-Sphere.h)

Structure factor :: Hayter-Penfold (SQ-HayterPenfold-MSA.h)

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I(Q) = I0 x P(Q) x S(Q) + bgd;

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P(Q)= F2(Q,r)

F(Q,r) = 3 ( sin( rQ ) - rQ cos( rQ ) ) / ( rQ )3;

I0= eta * volume * contrast ... ( could be adopted to a task) ______________________________________________________________

S(q) :: Hayter and Penfold structure factor for macroion solutions.

Routine to calculate S(Q) for a screened Coulomb potential between finite particles of diameter 2xR_SQ

at any volume fraction eta.

Reference:

J.B. Hayter And J. Penfold, Mol. Phys., 1981, 42, pp.109-118.

Code History:

1. Fortran Code: J.B. Hayter And J.F. Billman;

2. Convertation To C-Code [For Sasfit]: J. Kohlbrecher & I. Bressler

3. Adoption To Qtikws : V. Pipich

[x] Q [y] I [parameter names] R,R_SQ,Z,salt,dielectric_constant,T,rhoE,rhoS,I0,N,eta,V,bgd,currentOutput,numberOutputs, [initial values] 50[10..10000],125[1..10000],2[0..100],0[0..1000],78[0..100],298[0..1000],3e+10[-0.6e+10..7e+10],6.33e+10[-0.6e+10..7e+10],1,1,0.4[0..1],1,0[0..2],0[0..3],2 [adjustibility] 1,0,0,0,0,0,0,0,0,0,0,0,0,0,0 [parameter description] PQ :: Semi-Axe Length [A],SQ :: effective radious of interaction [A],SQ :: Effective charge ,SQ :: Salt concentration [M],SQ :: Dielectric constant ,SQ :: Temperature [K],I0 :: SLD of solvent [cm^-2],I0 :: SLD of solvent [cm^-2],I0 :: [calculated] forward scattering I(Q=0)=eta V contrast [cm^-1],I0 :: [calculated] number density of ellipsoids N=eta/V [cm^-3],I0 :: volume fraction of ellipsoids ,I0 :: [calculated] volume of ellipsoids [A^3] V=4Pi/3 epsilon R^3 [A^3],bgd :: background [cm^-1] ,output: 0 - full function; 1 - formFactor; 2-structureFactor; 3 - SQ=1,number of individual outputs, [h-headers] #include "IncludedFunctions/pq-sphere.h" #include "IncludedFunctions/sq-hayter-penfold-msa.h" [included functions] [code] //+++ [I0-part] :: I0 ::some constant calculations V= sphere_volume(R); // calculation of Volume :: V if (V!=0) N=eta/V*1e24; // calculation of number density :: N I0=eta*V*pow(rhoE-rhoS,2.0)*1e-24; // calculation of forward scattering :: I0 //+++ [main-part] :: actially calculation of function here double SQ = sasfit_sq_HayterPenfoldMSA(Q, R_SQ, Z, eta, T, salt, dielectric_constant); double PQ= sphere_form_factor (Q,R) ; // Form-factor of Sphere I = I0 * PQ * SQ + bgd; // PQ and SQ coupling :: isotropic case //+++ Output switcher (standard currentOutput=0) if (currentOutput==1 || currentFunction==1) I=I0*PQ ; // output :: form-factor x I(0) if (currentOutput==2 || currentFunction==2) I=SQ ; // output :: pure structure factor S(Q) if (currentOutput==3 || currentFunction==3) I=PQ ; // output ::pure form-factor [fortran] 0, [end]