Checkcif, CCDC

I feel that checkCIF (and by extension, CCDC) is growing increasingly hostile to us crystallographic bottom-feeders who ply our trade with powder diffraction data. I'm sure that members of this group share my frustration in getting inappropriate complaints like a missing Flack parameter, _diffrn_m

Re: ITC scattering factors: Table 6.1.1.1: Ne

The 1992 edition lists 2.790 for s = 0.60 and 2.517 for 0.65, so I guess that tells you when the error appeared. On a side note, and at some risk of being flamed, I'm curious why any crystallographer would care. Best to all, Peter ** Peter W. Stephens SUNY Distinguished P

ITO source code

Does anybody know where I can find the source code of the powder indexing software ITO? All the best, Peter ** Peter W. Stephens SUNY Distinguished Professor Emeritus Department of Physics and Astronomy Stony Brook University +++

Structure Solution and Poorly Crystalline Materials

Friends and colleagues, We are organizing a microsymposium at the 2020 IUCr meeting on the topic of Structure Solution and Poorly Crystalline Materials. We want to feature important recent work, especially that points toward the future development and diffusion of knowledge in this topic. If you

Re: Noise in XRD

Use of a chopper won't improve on the limit imposed by shot noise. You're probably better off chasing down the cause of the low angle background. ** Peter W. Stephens Professor, Department of Physics and Astronomy Associate Dean for Research and Facilities, College of Art

Re: Automated XRD Date

Jim, \What do you mean by automated? Controlled by a computer with (presumably) stepping motors? Robot sample changer? ** Peter W. Stephens Professor, Department of Physics and Astronomy Associate Dean for Research and Facilities, College of Arts and Sciences Stony Brook

Re: have you seen this kind of problem with a NaI detector?

I don't have an answer to all the symptoms you describe, but it seems likely that your scintillator has died. Loss of intensity and of detector energy resolution sound like water has gotten into the (very hygroscopic) NaI scintillator. When it happened to me, it was with a Bicron detector. Don't re

Re: card #04-017-70854

I believe that if you contact the ICDD directly, they will be happy to provide. ** Peter W. Stephens Professor, Department of Physics and Astronomy Associate Dean for Curriculum, College of Arts and Sciences Stony Brook University (631) 632-8156 http://mini.physics.sunysb.

Re: Site occupancies refinement

You seem to be confusing beq (thermal parameter) with site occupancy. At a start, I would think that the site would have the same thermal parameter for either atom, and refine occupancies that sum to unity. For example, site A1 occ Fe feocc .9 x 0 y 0 z Az .055 beq Abeq 2 site A2 occ Ru =1-feocc;

Re: Preferred orientation and lattice parameters

How much mismatch? If you're getting a good profile fit, I'd be inclined to doubt that it is a consequence of preferred orientation. You could mix your sample with another material (corundum powder, cork) to try to reduce the degree of preferred orientation, and see if that makes a difference. I