Let me add one small thing to what Peter said. Be careful to check that you truly have a converged density. It is possible for the scf iterations to converge to a trap where the density (:DIS etc) is converged but the orbital terms (:MVORD) are not self-consistent. I would estimate that for a self-consistent orbital potential :MVORD should be less than 1%. It can be necessary to take some measures to climb out of local traps like this, for instance by doing "echo 0.1 > .pratt" to force a Pratt step to be included. This can be important when -so is included, and in a few cases when it is not.
On Mon, Nov 23, 2015 at 7:45 AM, Santu Baidya <santubaidya2...@gmail.com> wrote: > Dear Prof. Blaha, > > Thank you very much for you reply on this. Actually I did relax the > structure under GGA+U approximation. Then took two approaches. In one case > I did SCF calculation under GGA+U with relaxed structure and added SOC > afterthat. In other case I took relaxed structure and did GGA+U+SOC > calculation. > Which gave me two different electronic structure for the same relaxed > structure. > > So I have to take lowest energy structure. > > Thanking you and regards, > > Santu Baidya > > > > > > On 23 November 2015 at 18:58, Peter Blaha <pbl...@theochem.tuwien.ac.at> > wrote: > >> It is well know that GGA+U calculations can end up in different states >> (see previous posts). >> >> If you have used the same parameters, you should use the total energies >> of the two calculations and the one with lower energy should be the better >> one (but not necessarily the best !) >> >> In any case, I always recommend: >> >> First do a standard GGA calculation (also check forces, if they are >> small). >> Then add SO and do a GGA+SO calculation (if you really have heavy >> elements?) >> x lapwdm -up -so to generate density matrices >> >> and finally add the "U" and do GGA+so+U >> >> There is, however, no guarantee that you find the lowest energy ground >> state ! Sometimes it is good to start with a smaller U-value than >> anticipated. >> Sometimes you may do a structure relaxation at the GGA-level and use this >> structure, >> or a structure relaxation at GGA+U (no SO). >> >> If SO is not a major effect, I'd first do everything without SO. >> >> ------------------- >> From these advices you can see that there is not a unique and save way, >> which works in all cases. >> >> >> >> On 11/23/2015 12:10 PM, Santu Baidya wrote: >> >>> Dear Prof. Blaha and wien2k users, >>> >>> I use wien2k version WIEN2k_14.1. Recently I did spin-orbit >>> coupling calculation under GGA+U+SOC approximation with two different >>> approaches- one starting from collinear ground state and another >>> starting from scratch (random wavefunction). Two approaches give me >>> completely different results -metal and insulator. >>> >>> Please tell me which approach should I accept as solution. >>> >>> I look forward to get reply. >>> >>> Thanking you, >>> >>> Santu Baidya >>> University of Duisburg-Essen >>> Duisburg >>> >>> >>> >>> >>> _______________________________________________ >>> Wien mailing list >>> Wien@zeus.theochem.tuwien.ac.at >>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >>> SEARCH the MAILING-LIST at: >>> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >>> >>> >> -- >> >> P.Blaha >> -------------------------------------------------------------------------- >> Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna >> Phone: +43-1-58801-165300 FAX: +43-1-58801-165982 >> Email: bl...@theochem.tuwien.ac.at WIEN2k: http://www.wien2k.at >> WWW: http://www.imc.tuwien.ac.at/staff/tc_group_e.php >> -------------------------------------------------------------------------- >> _______________________________________________ >> Wien mailing list >> Wien@zeus.theochem.tuwien.ac.at >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> SEARCH the MAILING-LIST at: >> http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >> > > -- Professor Laurence Marks Department of Materials Science and Engineering Northwestern University www.numis.northwestern.edu Corrosion in 4D: MURI4D.numis.northwestern.edu Co-Editor, Acta Cryst A "Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Gyorgi
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