[mcstas-users] Debye-Waller factor

[Peter Kjær Willendrup]

Dear Dimitri,


On 30 Sep 2018, at 15.19, Дима Шапиро <shapirod at mail.ru<mailto:shapirod at mail.ru>> wrote:

I have a question concerning Debye-Waller factor in the component PowderN. What should I substitude here?
In manual it's written that DW factor is exp(-2W). Is this W the same as thermal parameter B, which is connected with root-mean square diversion from equilibrium of atoms <u^2>?

Yes, it is my understanding that this is the case.

How should I take into account dependence of DW on scattering vector q (i.e. on scattering angle)?

I had a look in our distributed datafiles of which none currently has an explicit column defined for DW, my understanding is therefore that this factor is typically included in the |F^2| column.

If you believe this is not the case in the datafile you are using, you could try to experiment with adding a DW column in the datafile and either this in the header:

#column_DW 16
(16 of course needs replacement with whatever column number you have)

or using the format specifier, i.e.

format={j,d,F2,DW,delta_d_d/d,1/2d,q,F,Strain}

where all of the above numbers in the curly brackets refer to column indices in your file.



Best and hope this helps,

Peter Willendrup

Peter Kjær Willendrup
Forskningsingeniør, Speciakonsulent
Næstformand for DTU Fysik LSU



DTU Physics

[cid:image001.gif at 01CCCAF1.5E6331F0]

Technical University of Denmark



[cid:image002.gif at 01CCCAF1.5E6331F0]


Department of Physics
Fysikvej

Building 307

DK-2800 Kongens Lyngby

Direct +45 2125 4612

Mobil +45 2125 4612
Fax +45 4593 2399


pkwi at fysik.dtu.dk<mailto:pkwi at fysik.dtu.dk>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman2.mcstas.org/pipermail/mcstas-users/attachments/20181003/e3eb5898/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.gif
Type: image/gif
Size: 58 bytes
Desc: image001.gif
URL: <http://mailman2.mcstas.org/pipermail/mcstas-users/attachments/20181003/e3eb5898/attachment-0002.gif>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image002.gif
Type: image/gif
Size: 1055 bytes
Desc: image002.gif
URL: <http://mailman2.mcstas.org/pipermail/mcstas-users/attachments/20181003/e3eb5898/attachment-0003.gif>