Dear FEFF users, I am trying to calculate F K-edge XANES of some hydrogen containing solid (several model compounds imitating partially fluorided hydroxyapatite) by FEFF8.20.Some of the calculation was done without trouble. However in a certain model (see the attached file "feff_inp_1.txt"), the calculation stops with following error messages: WARNING: fatal error in subroutine corval. Try to reduce ca1 in SCF card. If does not help, SEND bug report to AUTHORS CORVAL-1 (Please see also the attached file "log1_dat_1.txt".) Following the advice in the error message, I changed ca1 in SCF card to 0.1 or 0.05, but unfortunately it did not work. Then I changed the folp parameter in FOLP card (determining the magnitude of overlapping the muffin-tin radii) as follows, FOLP 4 0.8 and actually it did work. (If I am correct, this option means folp for the other potentials are all set to be 1.0. )
I don't think so : for the other atomic species it remains to the default value (1.15).
However, I doubt this results because the shape of simulated XANES for the othermodel by default folp (AFOLP) is significantly different from that by modified folp (FOLP 4 0.8).I am wondering if there are "strategies" for determining appropriately the folpparameters. If there is, could someone kindly give me the advice?
No general strategie, look at the appendix of the paper of JJ Rehr and RC Albers (Reviews of Modern Physics, Vol72, n°3, July 2000, p. 621) who discussed about that. But be happy with your result: in fact Pot 4 is for H if I read your input file, and H is a small atom: so why not folp 0.8 for H? But look at the charge transfer to check is there is some sense from the physical point of view.
Best Regards, M. Jaouen -- __________________________________________ Michel Jaouen Universite de Poitiers - UFR Sciences - SP2MI LMP UMR 6630-CNRS Boulevard Pierre et Marie Curie - Teleport 2 BP 30179 86962 Futuroscope - Chasseneuil Cedex France Tel : (33) 5 49 49 67 37 Fax : (33) 5 49 49 66 92 e-mail : Michel.Jaouen@univ-poitiers.fr __________________________________________