Thank you very much for your response, I will follow your suggestion and run the case with MSEC1 just to make sure. I will report my results later
Once again Thank you all for the help. David G. Department of Physics California State University - Los Angeles On 01/09/2011 11:40 AM, tran at theochem.tuwien.ac.at wrote: > Dear David, > > 0.4 is probably large enough such that pseudo-convergence should not > happen. Nevertheless, if you want to be sure that it's ok, you can > restart the calculation (after having done save_lapw) with the default > mixing parameters in case.inm (MSEC1 with 0.2). > > F. Tran > > On Sun, 9 Jan 2011, David wrote: > >> Professo Blaha, >> >> Thank you very much for your reply. Since the beginning of my calculation >> I've >> been taking care of the mixing factor as you recommended. Now the calculation >> seems to be approaching to convergence. >> >> However I'm a little concerned now about what you call "pseudo-convergence" >> how can I evaluate if my calculation came to a full convergence or a >> pseudo-convergence? >> >> By the way the mixing factor I'm using right now is 0.4 with the PRATT mixing >> scheme, is this such a small mixing factor that could lead to >> pseudo-convergence? >> >> Thank you very much for you help Dr. Blaha. >> >> David Guzman >> Department of Physics >> California State University - Los Angeles >> >> On 01/09/2011 01:16 AM, Peter Blaha wrote: >>> Convergence of mBJ calculations is sometimes a bit tricky since not only the >>> charge density but also the kinitic energy density (or the "vresp"-files) >>> determine the potential. >>> >>> The recommended way is to start out with a PRATT mixing (with eg. 0.2) >>> and once the :DIS has settled a bit (decreased from the initially big >>> values, but then not changing much, usually after ~10 iterations) one can >>> graduadely increase the mixing factor (to eg. 0.3 and 0.4). Maybe >>> :DIS increases a little, but as long as there are no oszillations in ENE or >>> ::GAP this is fine. >>> Eventually, one may intermediately "save" the calculations (to have a >>> restarting point) and continue with MSEC1, since once the vresp-files are >>> partially converged, density-mixing as done with MSEC1 should be fine. >>> Please be aware, that in mBJ-calculations not only the density (clmsum) is >>> mixed, but that the mixing-factor in case.inm also mixes the >>> exchange-potential in lapw0. Thus, there is a danger of "pseudo-convergence" >>> when the mixing factor is too small. >>> >>> Am 09.01.2011 00:31, schrieb David: >>>> Dear Professor Blaha and Wien users, >>>> >>>> I'm running mBJ calculations for CuZrTiO5, spin-polarized, it has 16 >>>> atoms in the unit cell, and im running 300 k-points. My ultimate goal is >>>> to get the band structure of this crystal. >>>> >>>> I haven't got any problems regarding code errors, in fact up to now >>>> everything has run very smooth. My question though is the following: the >>>> has has run 58 cycles now and the charge distance does not seem to >>>> reduce significantly, in fact for the first 45 cycles or so it reduced >>>> very slow, but now it's going up again, I was wondering if this is a >>>> common behaviour? Also I was wondering if there is any way I can make it >>>> converge faster, I know this is a large calculation, but may be some of >>>> you guys have suggestions. >>>> >>>> Some details about my calculation: >>>> >>>> 1. I run a regular spin-polarized scf cycle using the MSEC1 with a >>>> mixing factor of 0.2 and it converged in 18 cycles (convergence criteria >>>> was charge: 0.00001 e) >>>> >>>> 2. I followed the steps for mBJ calculations from the manual, I used >>>> PRATT with a mixing factor of 0.2 and the convergence criteria is >>>> charge: 0.00001 e >>>> >>>> 3. Attached are the case.struct and case.inst if it helps >>>> >>>> Please if you required any other information in order for me to get some >>>> help, I can send it >>>> >>>> Thank you very much >>>> >>>> David Guzman >>>> Department of Physics >>>> California State University - Los Angeles >>>> >>>> >>>> >>>> _______________________________________________ >>>> Wien mailing list >>>> Wien at zeus.theochem.tuwien.ac.at >>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> _______________________________________________ >> Wien mailing list >> Wien at zeus.theochem.tuwien.ac.at >> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien >> > _______________________________________________ > Wien mailing list > Wien at zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien