y = sf_square_well(p, x, [y]) : structure factor of particles interacting with a square well potential [Sharma]
iFunc/sf_square_well structure factor of particles interacting with a
square well potential [Sharma]
The 'x' wave-vector/momentum axis is usually in nm-1 or Angs-1.
Typical values for parameters are
R=10 Angs, rho=0.02, epsilon=1.5*T, Delta=1.2*RHS
The model returns the S(q) structure factor.
Ref: Sharma, R. V.; Sharma, K. C. Physica, 89A, 213. (1977).
Extracted from sasfit/sasfit_sq/sasfit_sq_SquareWell2.c
I. Bressler, et al, Journal of Applied Crystallography, 2015, 48 (5), 1587-1598
input: p: square well potential model parameters (double)
p = [ R=Hard_Sphere_Radius rho=Volume_Fraction epsilon=Well_Depth_K Delta=WellWidth T=Temperature_K]
or 'guess'
x: wave-vector/momentum axis (double, e.g. nm-1 or Angs-1)
y: when values are given and p='guess', a guess of the parameters is performed (double)
output: y: model value (intensity S(q))
ex: y=sf_square_well([50 0.05 15 10 10], -10:10); or plot(sf_square_well,[10 0.02 15 10 10], 0:0.01:1)
Version: Aug. 22, 2017
See also iFunc, iFunc/fits, iFunc/plot
(c) E.Farhi, ILL. License: EUPL.