Hi, I wanted to get some advice on a vanadium centered material I’ve been trying to fit for quite a while w/ repeated failure. Based on XRD and electrochemistry I’m pretty confident in the material/model, and I have the input file for the material. The first shell out to 2.2 angstroms in R space is a distorted VO6 w/ bond lengths ranging from 1.6 to 2.2 angstroms, similar to the V2O5 which has been discussed on the mailing list recently (July 7th). The last two peaks from 2.2 to 3.3 angstroms presumably include 4 V-P and 1 more V-O single scattering paths. (the best fit I could get on the 4V-P/1V-O used only the first of these two peaks.) With regards to the first shell fitting, is it appropriate to be grouping the V-O bonds in terms of 1 short, 4 medium, and 1 long bond distance to cut down on variables? I noticed in the V2O5 previously discussed, that he used one ss and delr term for all 6 V-O paths, but I guess that just means making some assumptions that any variations in ss and delr are isotropic throughout. Is that correct? I’ve had real issues w/ those peaks representing V-P/V-O from 2-3.3 angstroms so I wonder if it’s unreasonable to try and extract this information based on the k space or if possible thats not what I have there. Could it be that I need to account for the two inequivalent V centers? (In that case, wouldn’t the number of variables be doubled?) Thanks for any comments, Chris -- Chris Allen Northeastern University Center for Renewable Energy Technology 317 Egan Research Center 360 Huntington Ave. Boston, MA 02115 617-373-5630