On Thursday 27 July 2006 14:22, Matthew Marcus wrote: > Other reasons for the popularity of FEFF include its longer history,
Actually the early references for both GNXAS and FEFF6 date from 1991. To paraphrase Steve Zabinsky (the fellow who did much of the work on Feff6) "if you make it easy to use, everyone will use it -- even if it's not better". > its distribution as source, so > it can be recompiled for any system, and not least, IFEFFIT/Artemis! I'd say that today this mailing list contributes to Feff's wide adoption at least as much as the codes that are the topic of the list. > What is this 'interesting approach'? Matt and I were solving materials physics problems in grad school, so our codes are very well suited to problems involving crystals or other things with fairly well known atomic positions. Adriano and Andrea were (I think, but I could be mistaken) solving problems more along the lines of solvation chemistry and highly disordered material. Consequently (and explained in broad brushstrokes) GNXAS is well suited to problems for which the g(R) is not described by discrete atomic positions. In essence, GNXAS integrate the exafs equation over a functional form of g(R). It is certainly possible to deal with high disorder in Feff-base analysis and it is certainly possible to do material science-y problems with GNXAS -- they really aren't that fundamentally different. If you are looking at amorphous solids or solvated ions (or really any other system) you would be wise to look into GNXAS. You may find that it fits your problem or fits into your brain better than Feff, Ifeffit, and my software. > That reminds me - I'm a co-author on a paper, which was submitted to PRL, > in which we used FEFF8.1 > to simulate EXAFS. A referee complained that FEFF8.1 was for XANES, not > EXAFS. What was that > about? Ummm.... a high degree of confusion on the part of the referee perhaps? B -- Bruce Ravel ---------------------------------------------- [EMAIL PROTECTED] Molecular Environmental Science Group, Building 203, Room E-165 MRCAT, Sector 10, Advanced Photon Source, Building 433, Room B007 Argonne National Laboratory phone and voice mail: (1) 630 252 5033 Argonne IL 60439, USA fax: (1) 630 252 9793 My homepage: http://cars9.uchicago.edu/~ravel EXAFS software: http://cars9.uchicago.edu/~ravel/software/ _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
