Dear Prof. Laurence Marks Thank you very much for your answer *For the case of my calculations, I want to optimize the internal parameters of an atom of a **chalcopyrite**, **usually I used MSR1a without -min (old WIEN2k versions) :* *runsp -fc 1* *save xxx* *i change MSR1 to MSR1a * *runsp -fc 0.5 -ec 0.00001 -cc 0.001 * *is this method better than -min option? or it's the opposite*
Le lun. 15 oct. 2018 à 16:31, Laurence Marks <l-ma...@northwestern.edu> a écrit : > There is in my opinion no "right" method. The question is what are you > trying to do? > > Case 1: A structure with fixed positions or a problem where you "don't > care" about minor forces, e.g. calculating a simple bulk structure. Then > just "runsp -cc 0.0001 -ec 0.0001" is fine. (I prefer to use -cc as well as > the default -ec). > > Case 2: A simple structure where there might be minor forces that you do > care about. Then something like "runsp -cc 0.0001 -ec 0.0001 -fc 1" first > and check the forces. Iff they are too large for you, then "save -f -d > PreMin ; runsp -cc 0.001 -ec 0.0001 -min" or similar. > > Case 3: A more complex structure where you know the positions are not > quite right. I suggest using something like > runsp -cc 0.01 -ec 0.1 -fc 4 > save -f -d PreMin > runsp -cc 0.001 -ec 0.0001 -fc 1 -min > > This avoids converging too much at first when you know the result won't be > right until the internal minimization has been done. In addition, MSR1a > often works better when started from a partial minimization where the > density and pseudo-charges are somewhat converged. For a large problem add > "-noHinv", I have had problems with -min and -it in the past. > > On Mon, Oct 15, 2018 at 9:03 AM karima Physique <physique.kar...@gmail.com> > wrote: > >> Dear Wien2k user; >> >> According to user guide, after a SCF cycle with runsp -fc 1 we continue >> with run runsp -min >> I want to know which of these two methods is the correct one: >> 1) >> runsp -fc 1 >> runsp -min >> runsp -min -fc 0.5 -ec 0.0001 -cc 0.001 >> >> or >> 2) >> runsp -fc 1 >> runsp -min -fc 0.5 -ec 0.0001 -cc 0.001 >> > > > -- > Professor Laurence Marks > "Research is to see what everybody else has seen, and to think what nobody > else has thought", Albert Szent-Gyorgi > www.numis.northwestern.edu ; Corrosion in 4D: > MURI4D.numis.northwestern.edu > Partner of the CFW 100% program for gender equity, www.cfw.org/100-percent > Co-Editor, Acta Cryst A > _______________________________________________ > 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 >
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