• topas

  • Anomalous Scattering in TOPAS 4.2

Hello All,

I am a master's student at Durham trying to carry out some refinements of x-ray anomalous scattering data from Diamond's I11.

I have in front of me a demonstration of such a refinement which includes the potentially crucial line:

'load f0_f1_f11_atom f1 f11',

I have read that this allows the refinement of f' and f''. According to a "What's new in TOPAS 5.0?"This feature was added in TOPAS v5.0, and as such, does not work on the version of TOPAS I am currently using: v4.2.

My question is: does the ability to refine these parameters matter? In other words, is TOPAS v4.2 handling the adjustments to my model due to the absorption automatically, behind the scenes, but isn't allowing me to refine the values directly? Or do I need to somehow get access to v5.0?

Any help on this question would be greatly appreciated!

Regards,
Max
Hi Max

In V4 the file anomdisp.cpp is read for f’ and f’’ for Laboratory X-ray tubes if there are no associated SSF\*.NFF files or if use_tube_dispersion_coefficients is defined.

If there is an SSF\*.NFF file and use_tube_dispersion_coefficients is not defined then values from the SSF\*.NFF is used.
alan
Hi Alan,

Thank you so much for clearing this up for me, I really appreciate it. Time to do some refining!

Regards,
Max