HI Shelly, I wouldn't say it's wrong to use Feff8 for EXAFS analysis, just rarely necessary. Feff8 was definitely designed for XANES, and improvements for EXAFS were not the main goal. But there are a few cases where Feff8 _is_ known to be better for EXAFS than Feff6. (I'll leave out Feff7 as it seems no one is using this much). Clusters with H is one, and transuranic elements is another. I've heard a few people claim that Feff8 gives "better E0's", which I think means that E0 refines to a value closer to 0 (that is, to where the it's arbitrarily assigned in the data processing). Since E0 has to be refined and has little physical significance, I don't find this to be a compelling advantage for Feff8. Early versions of Feff8 (pre-release? Including 8.00?? I'm not sure) were much worse for EXAFS.This did get fixed, but I'm not sure when (I have a hard time understanding Feff8 version numbers and can never really tell which get released and widely used: I've given up complaining and live wih the fact that "Feff8" means one snapshot of 8 years worth of work.). By Feff8.1 for sure, and maybe eralier, there were essentially no difference between Feff6, 7, and 8 for EXAFS. That was based on analysis of data on metal foils (Cu, Ag, Au), and could hardly be called thorough and possibly not even 'highly relevent to real-world problems', as it doesn't even test changes in exchange or overlap of metal-oxygen potentials. Better testing and comparisons would be very good. Anyway, I think it's fine to use Feff6, 7, or 8 for EXAFS. I don't think anything should change for these versions in the reporting of how a Feff calculation was done for EXAFS. Most EXAFS work using Feff give no details about the calculation, and I think that's mostly OK, as the Feff/Atoms/Artemis default parameters are generally quite reasonable. If the work discusses comparing different Feff calculations, then obviously more detail on what was changing would be needed. That's my opinion, anyway. --Matt