Dear Jon and Andreas, I did not, actually, expect such a deep online analysis of the pattern ;-) Yes, this small feature seems to be related to isolated 2D defects.
Best regards, Leonid ******************************************************* Leonid A. Solovyov Institute of Chemistry and Chemical Technology 660036, Akademgorodok 50/24, Krasnoyarsk, Russia http://sites.google.com/site/solovyovleonid ******************************************************* ----- Original Message ----- From: Andreas Leineweber <a.leinewe...@is.mpg.de> To: rietveld_l@ill.fr Cc: Sent: Monday, April 7, 2014 2:21 PM Subject: Re: Stacking faults and antiphase boundary Dear all, I think Jon is right. In the case of Cu this is the position of a (100) reflection of a hcp polytype. I have seen this feature in a couple of cases, and presence of this feature is sometimes taken as a sign for a two-phase character of the specimen, which need not be the case (other reflections from the hcp-like polytype generally are then lacking). In the case of Copper or alpha-Cu alloys a real two-phase character of the material is very unlikely. Diffax and Diffax_plus are able to model this feature. The mentioned ice example is reported in some more depth in PNAS 109 (2012) 21259 Best regards Andreas On 07.04.2014 09:05, Jonathan WRIGHT wrote: > > On 06/04/2014 08:06, Leonid Solovyov wrote: >> The faulting model in DDM gives nearly perfect agreement with the >> experiment: >> http://sites.google.com/site/ddmsuite/home/Copper-DDM.png >> > > It looks a little bit reminiscent of this pattern for ice: > > http://www.science24.com/paper/15441 > > ...but the little step at about 40.5 degrees doesn't seem to be in the > model? Isn't that coming from some sort of defects or diffuse > scattering? Not that I would attempt to model something like that, but > a 1D "rod" in 3D reciprocal space (coming from 2D defects) gives > step-like profiles in a 1D powder pattern. Although you generally only > know that if you've also got data from a single crystal :-) > > Cheers, > > Jon > -- Dr. Andreas Leineweber Max-Planck-Institut fuer Intelligente Systeme (ehemals Max-Planck-Institut fuer Metallforschung) Heisenbergstrasse 3 70569 Stuttgart Germany Tel. +49 711 689 3365 Fax. +49 711 689 3312 e-mail: a.leinewe...@mf.mpg.de home page of department: http://www.is.mpg.de/de/mittemeijer ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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