Could be helpful: RbBr, KBr, RbCl, AgBr(x)Cl(1-x) etc.l: A. Frenkel, E. A. Stern, M. Qian, and M. Newville, Multiple - scattering x-ray-absorption fine-structure analysis and thermal expansion of alkali halides, Phys. Rev. B 48 , 12449 (1993). A. Frenkel, E. A. Stern, A. Voronel, M. Qian, and M. Newville, Buckled crystalline structure in mixed ionic salts, Phys. Rev. Lett., 71 , 3485 (1993). A. Frenkel, E. A. Stern, A. Voronel, M. Qian, and M. Newville, Solving the structure of disordered mixed salts, Phys. Rev. B 49 , 11662 (1994). A. Frenkel, A. Voronel, A. Katzir, M. Newville, and E. A. Stern, Buckled crystalline structure of disordered mixed salts, Physica B 208 & 209 , 334 (1995). Anatoly ________________________________ From: ifeffit-bounces@millenia.cars.aps.anl.gov on behalf of Joseph Washington Sent: Wed 4/1/2009 1:55 PM To: XAFS Analysis using Ifeffit Subject: [Ifeffit] Mixed Multiple scattering shell Hello all, I was wondering if anyone can send any useful hints or tips for parameterizing a mixed multiple scattering shell comprised of two NaCl type strucutres, like the AgBr(1-x)Cl(x) example. Has anyone worked on fitting the third shell in that example? I am looking for examples of nacl rocksalt-like FEFF calculations that have successfully parametrized multiple scattering path contributions. Right now, after running feff, I'm using a different delr / ss term for each multiple scattering path I include. Does anyone have any clever ways of representing these in terms of the delr/ss in the first shell? Also, FEFF is telling me that the amp and mixing terms are almost completely correlated and this cause the amp term to blow up. Thanks all, I really appreciate the assistance! Joseph