niko1111
Hi
I am a new Topas user and trying to use PO_Spherical_Harmonics when fitting the pattern
I already know the terms of PO_Spherical_Harmonics in cubic system like:
PO_Spherical_Harmonics(sh_5551e527_2, 8 load sh_Cij_prm
{ k00 !sh_5551e527_2_c00 1
k41 sh_5551e527_2_c41 -0.1777376624
k61 sh_5551e527_2_c61 -0.04175920455
k81 sh_5551e527_2_c81 0.07476470259 } )
then I wonder how to use it in hexagonal system? thx
johnsoevans
Topas will generate the necessary terms for you. If you use e.g. jEditto set up your input file all you specify is the order of the spherical harmonic (usually 4, 6 or 8). First time you run topas it will generate the correct terms for a given symmetry in the format of your post.
niko1111
thanks for your reply, John.
But I can't find the PO_Spherical_Harmonics terms in JEdit.
Could you illustrate the operation to me?
lgermann
Hey,
Use the following in your input (for description have a look at the Technical Reference, p. 141)
spherical_harmonics_hkl sh
sh_order 4
Topas will automatically create all coefficients after the first refinement.
greets,
Luzia
johnsoevans
...or it's one of the clicks in the "simple Rietveld" menu