Hi,
I have a question related to GSAS and scattering factors : I am trying
to model orientationally disordered structures by using Bessel functions
(for those interested in this see Press and Huller, Acta. Cryst. 1973,
A29, 252). My question is how to input new scattering factors for
disordered molecules in Gsas. I was thinking that one may replace in
atmdata.dat file some values (I will not very often use Pu in my
refinements.. :-) but this may give trouble latter on (density, etc).
According to Gsas manual, page 181 : " EXPEDT can read a file containing
the scattering factor data as a function of sinθ/λ and fit it to the
needed function in subroutine EDTMFF".
Can anyone having experience with this give me hints on :
1. how to prepare and invoke such a data file
2. Is the subroutine EDTMFF fitting a three exponentials sum as in
Cromer data (with which will be difficult to fit a Bessel sperical
function or others) or just interpolate the values found in the file for
the required sin(theta)/lambda ?
Thanks for your attention,
N. Dragoe
