Instument parameter file

Hi! I am trying to refine some XRD data using GSAS and looking for an instrument parameter file for the Rigaku Dmax 2000 x-ray diffractometer. Can anyone help? Thanks Donna

Introduction

Hi! Just thought i'd quickly introduce myself as I am a new member. Currently a postdoc researcher in layered oxide materials. Donna

RE: Donna Arnold

I don't know the answer to Donna's question but would be interested in learning how one creates an instrument parameter file for a specific diffractometer if anyone cares to explain or point me in the direction of information describing this. Many thanks to Brian Toby for his space group

RE: Donna Arnold

A search in the Rietveld archives brings up a wealth of information: http://pcb4122.univ-lemans.fr/cgi-bin/searchrietveld.pl?Range=AllForma t=StandardTerms=instrument+parameter+file (old archive) http://www.mail-archive.com/cgi-bin/htsearch?method=andformat=shortco

Instument parameter file

Donna (and anyone else who wonders about this), In gsas\examples there is an iparm file (inst_xry.prm) that can be used for most any Bragg-Brentano powder diffractometer. These instruments all perform more or less equally independent of manufacturer with respect to the things of interest for

Re: Instument parameter file

Your sample will probably broaden the lines (LX, LY, etc.) so much that any attempt to vary the Gaussian coefficients will yield nonsense. Just some remark (of course, I am not a great specialist): At least to my experience, there is always some Gaussian broadening from the sample as well, and

Subscribing Unsubscribing to the Rietveld list

At 17:07 18/03/2004, Brian H. Toby wrote: Please remove me from the mailing list-thank you I seem to provoke the above response every time I post to the list... Perhaps :-) But you don't see the requests I have from new people wanting to join, which seem to increase whenever there is some

Note to software designers

Maxim V. Lobanov wrote: U, V, and W tend to be highly correlated, with a result that various combinations of quite different values can lead to essentially the same variance, sigma^2.These three parameters, therefore, do not converge in a stable manner when refined

Re: Instument parameter file

U, V, and W tend to be highly correlated The correlation between U,V,W is the result of a resolution curve that doesn't have a well defined minimum. If you differentiate the Caglioti equation for the FWHM: FWHM**2=U.tan**2(theta)+V.tan(theta)+W you obtain the condition for the minimum as

Re: Instument parameter file

Theoretically U,V,W should not be refined at all as they describe instrumental broadening, and this is exactly what I do (usually). After diffractometer alignment, a good quality pattern in whole possible angular range has to be collected from Rietveld standard which currently is LaB6. From

Re: Rietveld question - EXPGUI

I am going to give up my 'lurker' status on this mailing list to switch this thread to a more philosophical vein. In the past generation, many good crystallographers have also been good programmers. I suspect it was easier to learn programming than it was to teach crystallography to a

Re: Instument parameter file

Theoretically U,V,W should not be refined at all as they describe instrumental broadening This is true only when there is no Gaussian strain present. Brian