lanthanides convergence
Bruce, I am running feff to model XANES of Erbium doped ZnO. I have a big problem to find the convergence of FMS in this kind of systems. I increased the atoms number in feff code to nclusx=500 and still have not found convergence. Should I increase the nclusx to a bigger number?, is there a limit for this number independent from the computer RAM or I do have another chance?. Thanks for your time and patience. 8<- - - - - - 8<- - - - - - 8<- - - - - - 8<- - - - - - Eugenio H. Otal CINSO - CONICET - CITEFA eotal@citefa.gov.ar eugenioh@gmail.com 8<- - - - - - 8<- - - - - - 8<- - - - - - 8<- - - - - -
On Tuesday 26 August 2008 22:40:30 Eugenio Otal wrote:
Bruce, I am running feff to model XANES of Erbium doped ZnO. I have a big problem to find the convergence of FMS in this kind of systems. I increased the atoms number in feff code to nclusx=500 and still have not found convergence. Should I increase the nclusx to a bigger number?, is there a limit for this number independent from the computer RAM or I do have another chance?. Thanks for your time and patience.
Eugenio, 500 seems like a pretty big number. I am surprised that it is not enough to see convergence, but such things happen. I don't think there is a limit other than the amount of RAM. I think you can safely compile up a bigger version and let it go. If you post your feff.inp file, one of the people who reads the list who is more knowledgeable than I about the fine details of Feff8 might be able to give you some hints on how to obtain convergence faster. B -- Bruce Ravel ------------------------------------ bravel@bnl.gov National Institute of Standards and Technology Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2 Building 535A Upton NY, 11973 My homepage: http://xafs.org/BruceRavel EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/
Bruce, thanks for your answer, it is a great problem to increase the number of atoms, huge CPU time is needed to finish a calculation. Here I pasted the header and the first lines of the atom list and attached the whole file, if somebody could help me to reduce the calculation time I will be grateful. Thanks in advance, euG * This feff8 input file was generated by Artemis 0.8.011 * Atoms written by and copyright (c) Bruce Ravel, 1998-2001 TITLE name: ZnO:Er 1 at no distortion d= 4.136 TITLE formula: ZnO TITLE sites: Zn1,O1 TITLE refer1: wyckoff, vol 1, ch III, p 111 TITLE refer2: TITLE schoen: TITLE notes1: * Er L3 edge energy = 8358.0 eV EDGE L3 S02 1.0 * pot xsph fms paths genfmt ff2chi CONTROL 1 1 1 1 1 1 PRINT 3 0 0 0 0 0 *** ixc=0 means to use Hedin-Lundqvist * ixc [ Vr Vi ] EXCHANGE 0 *** Radius of small cluster for *** self-consistency calculation *** A sphere including 2 shells is *** a good choice *** l_scf = 0 for a solid, 1 for a molecule * r_scf [ l_scf n_scf ca ] SCF 4.0 *** Upper limit of XANES calculation. *** This *must* be uncommented to *** make Feff calculate full multiple *** scattering rather than a path expansion * kmax [ delta_k delta_e ] XANES 4.0 *** Radius of cluster for Full Multiple *** Scattering calculation *** l_fms = 0 for a solid, 1 for a molecule * r_fms l_fms FMS 5.00 0 *** Energy grid over which to calculate *** DOS functions * emin emax eimag LDOS -30 20 0.1 *** for EXAFS: RMAX 12.0 and uncomment *** the EXAFS card RPATH 0.1 *EXAFS 20 POTENTIALS * ipot Z element l_scmt l_fms stoichiometry 0 68 Er 3 3 0.001 1 30 Zn 2 2 2 2 8 O 1 1 2 3 68 Er 3 3 2 ATOMS * this list contains 902 atoms * x y z ipot tag distance 0.00000 0.00000 0.00000 0 Er 0.00000 0 -0.93804 -1.62473 -0.49466 1 Zn1 1.94019 1 1.87611 0.00002 -0.49466 1 Zn1 1.94023 2 -0.93804 1.62477 -0.49466 1 Zn1 1.94023 3 -0.93804 -1.62473 1.30173 2 O1 2.28346 4 0.93804 1.62473 -1.30173 2 O1 2.28346 5 1.87611 0.00002 1.30173 2 O1 2.28348 6 -0.93804 1.62477 1.30173 2 O1 2.28348 7 -1.87611 -0.00002 -1.30173 2 O1 2.28348 8 0.93804 -1.62477 -1.30173 2 O1 2.28348 9 0.93804 1.62473 2.10879 1 Zn1 2.82253 12 -1.87611 -0.00002 2.10879 1 Zn1 2.82255 13 0.93804 -1.62477 2.10879 1 Zn1 2.82255 14 0.93804 1.62473 -3.09811 1 Zn1 3.62187 21 -1.87611 -0.00002 -3.09811 1 Zn1 3.62189 22 0.93804 -1.62477 -3.09811 1 Zn1 3.62189 23 -3.75219 0.00002 -0.49466 1 Zn1 3.78466 24 1.87611 -3.24948 -0.49466 1 Zn1 3.78465 25 1.87611 3.24952 -0.49466 1 Zn1 3.78469 26 -3.75219 0.00002 1.30173 2 O1 3.97158 27 1.87611 -3.24948 1.30173 2 O1 3.97158 28 -1.87611 3.24948 -1.30173 2 O1 3.97158 29 3.75219 -0.00002 -1.30173 2 O1 3.97158 30 1.87611 3.24952 1.30173 2 O1 3.97161 31 -1.87611 -3.24952 -1.30173 2 O1 3.97161 32 2.81415 1.62475 2.60345 3 Er 4.16380 33 -1.87611 3.24948 2.10879 1 Zn1 4.30417 45 3.75219 -0.00002 2.10879 1 Zn1 4.30418 46
participants (2)
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Bruce Ravel -
Eugenio Otal