Hi all, First of all, kudos to Bruce and Matt on the new versions. One of my summer students more than once uttered the phrase "This is <italic>awesome</italic>" as she tried out yet another new feature. I concur. :) * * * I thought I'd share some non-transparent behavior on the part of feff6L as embedded in Artemis. It happens in a <italic>very</italic> common situation; I suspect many of you have been aware of this for years; for some reason I didn't really notice it enough to investigate until today: Use Artemis to put in an atoms file for Cu (fcc; a=3.61; one copper at 0,0,0). Choose a cluster size of 6. Run atoms, then feff. I get 22 paths ranging up to 6 angstroms. No problem. Repeat with cluster size 7. 41 paths now, up to 7 ansgstroms. Again, no problem. Now try cluster size 8. Now there are only 30 paths, with a maximum r of 6.35 angstroms! It turns out that what is happening is that feff is giving the error "internal path finder limit exceeded -- path list may be incomplete." And indeed it is. It just surprises me a little the manner in which it is incomplete...it's considerably worse off than the 7 angstrom cluster. There's an easy fix: feff defaults to evaluating paths with up to 8 (!) legs. If I override that to max out at 4 legs, then the cluster size can be pushed up as large as 9 without exceeding the path finder limit. In my opinion, the path finder limit in feff is high enough for most applications. I frequently fit up to 5 angstroms, which, considering the difference between reff and r and the width of EXAFS peaks, means I feel I have to include paths up to about 6 angstroms. But that means I need to have feff compute a cluster bigger than that (as has been discussed on this list a few times)...which makes a 7 angstrom cluster seem reasonable; maybe 8 for safety. I have never encountered a path with more than 4 legs that I found to be significant. So for me this is not a problem. But with novices in mind, I see two improvements that could be made: 1) Artemis now does a decent job of flagging users when iffeffit encounters a problem. Perhaps it should do the same for feff. (I know the feff error messages are often somewhat obscure. But if Artemis simply stated that "FEFF has encountered a possible problem" and advised users to check the messages screen, the behavior might seem a tad less baffling.) 2) Does anyone out there run into cases where paths with more than 4 legs are significant? If not, Artemis should just stick the card NLEG 4 into the feff.inp file automatically...that's probably a better default value. Of course, a knowledgeable user could still override that to include more legs if they wished. --Scott Calvin Sarah Lawrence College