[RMCProfile-users] Does XRAY_REAL_SPACE_DATA keyword implemented?

Martin Dove martin.dove at qmul.ac.uk
Tue Dec 6 09:41:26 GMT 2016


Dear Eduard

The assumption we (developers) have made is that you will use the scattering data for x-rays. The x-ray PDF is slightly contrived in that it attempts to deconvolve the effects of the electrons (which scatter the x-rays) by a method that can only at best treat atoms as average atoms. So the x-ray PDF for materials containing more than one atom type is not quite the same as the neutron PDF, where the scattering is from the point-size nuclei.

It is my intention one day to try to build in support for x-ray PDFs but that will be done in a different way to how RMCProfile currently works.

You can treat it like a neutron one and feed in manually the effective scattering lengths (namely the atomic number) but take account of my warning that the x-ray PDF is not really a properly-weighted PDF.

Best wishes

Martin


> On 30 Nov 2016, at 14:45, Eduard Levin <sliderzzzzz at gmail.com> wrote:
> 
> Dear all,
> 
> I'm just starting with RMCProfile, and I have some synchrotron data I'd
> like to model. The problem is that, in the manual, it's not specified that
> G(r) from X-Rays could be used. (I can make it mimic neutron data, but
> maybe there's a batter way.)
> Is it related to version 6.5.2 exclusively, and is changed in recent
> releases, or should I try using G(r) as if they're from neutron scattering?
> 
> Kind regards,
> Eduard Levin
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