[Ifeffit] Vanadium-Chromium Prussian Blue Analog XANES fitting

2015-07-30 Thread Adora Graham
Hello, First of all, I am still very new to XAS analysis, so please excuse any misunderstandings I may have. I have a series of compounds nominally consisting of KxVx[Cr(CN)6] Prussian blue analogs (where x is ~1) with Cr(III) and presumably V(II) present in the system. From other evidence, the V

Re: [Ifeffit] Vanadium-Chromium Prussian Blue Analog XANES fitting

2015-07-30 Thread Chris Patridge
The standard curve using V standard, how are you making the curve? You probably know from the Wong paper that there are pre edge features for the vanadium oxide species. We used a very similar method to assign oxidation states to doped vanadium oxide compounds between 3-5. The method gave us r

Re: [Ifeffit] Vanadium-Chromium Prussian Blue Analog XANES fitting

2015-07-30 Thread Matt Newville
Adora, On Thu, Jul 30, 2015 at 6:38 PM, Adora Graham wrote: > Hello, > > First of all, I am still very new to XAS analysis, so please excuse any > misunderstandings I may have. > > I have a series of compounds nominally consisting of KxVx[Cr(CN)6] > Prussian blue analogs (where x is ~1) with Cr(

Re: [Ifeffit] Vanadium-Chromium Prussian Blue Analog XANES fitting

2015-07-30 Thread Adora Graham
Matt, "It can be challenging to extrapolate from XANES with different ligands, and Prussian Blue with linear CN ligands might act quite differently from O ligands. Like, I wouldn't necessarily suspect the VS04 was a particularly good reference for you, though I could be wrong." I think this is

Re: [Ifeffit] Vanadium-Chromium Prussian Blue Analog XANES fitting

2015-07-31 Thread Chris Patridge
If you have Dr. Whittaker-Brooks data then you have the work we did on vanadium oxides. You can look at some of the other vanadium papers we did. Chris Sent from my iPhone > On Jul 30, 2015, at 11:49 PM, Adora Graham wrote: > > Chris, > > I have attached a copy of the correlation plot that

Re: [Ifeffit] Vanadium-Chromium Prussian Blue Analog XANES fitting

2015-07-31 Thread Adora Graham
Chris, It looks like your other vanadium papers all seem to involve vanadium oxides in different oxidation states. While I think this method works very well for metal oxides, in my case there should only be isocyanides bound, from the vanadium perspective (not counting defect sites), so I'm not fu

Re: [Ifeffit] Vanadium-Chromium Prussian Blue Analog XANES fitting

2015-07-31 Thread Carlo Segre
Hi Adora: FEFF9 does a pretty good job of calculating XANES now. YOu might want to try using that to confirm what you think you have. I agree with you that having an environment similar to your target compound is essential for calibration of valence. Carlo On Fri, 31 Jul 2015, Adora Grah