Re: thermal parameters at low temperature

[Andreas Leineweber]

Dear Liliana,

if the model is correct, and variable site occupancies can be excluded and the chosen scattering lengths are correect,
it is likely that some 2theta-dependent or time-flight-dependent (if time of flight diffractometer was used) effects (e.g. absorption, Lorentz factors) are not correctly considered, although neutron diffraction is less sensitive than X-ray diffraction.

Best regards
Andreas

Marilena L Viciu schrieb:

 

Dear all,

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I am refining a powder neutron data at low temperature (50K). I got some of the thermal parameters negative although the model seems to be quite right (the data at room temperature behaved well with the same model). From your experience, is this the case of a wrong model?

I really appreciate any comment!

Thank you!

Liliana

--
Dr. Andreas Leineweber
Max-Planck-Institut fuer Metallforschung
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