[Wien] Finally the report about optimizing the structure with MSR1a and mBJ

Luis Carlos Ogando Dacal ogando at ieav.cta.br
Tue Sep 11 19:09:31 CEST 2012

Dear Prof. Marks,

   Thank you for the comments.
   As I said before, I took the convergence criteria from literature
(pseudopotential, not lapw) and as they worked fine for MSCE1 with
PBE, I supposed that they should also work with MSR1a-mBJ.

   Anyway, I will try again the optimization, but using the options
you suggested. As soon as possible, I will report the results.
   By the way, I have fixed atoms because I am trying to simulate a
system composed by a substrate with a cap layer, so only the cap layer
atoms are relaxed.
   All the best,

2012/9/11 Laurence Marks <L-marks at northwestern.edu>:
> The convergence criteria are about 100 times too small to be
> realistic. Use -ec 0.0001 at most, and -fc has no bearing for MSR1a; I
> suggest adding -cc 0.00025. With what you have used you are limited by
> the noise of the iterative method. If you look in the documentation,
> you will see that -vec2pratt is recommended (by me) as it is better
> with MSR1a.
> When you say "some atoms were fixed" what do you mean? For a
> non-centro symmetric structure it is OK to fix one atom, but if you
> fix more then your results may well be unphysical.
> What matters is not whether MSR1a works with mBJ (it does), rather
> whether the atom positions are better in some sense.
> On Tue, Sep 11, 2012 at 8:36 AM, Luis Carlos Ogando Dacal
> <ogando at ieav.cta.br> wrote:
>> Dear Prof. Blaha, Marks and WIEN2k community,
>>    I finally tried the structure optimization using MSR1a and mBJ
>> (without SOC).
>>    As I have a previous successful optimization of the structure using
>> MSEC1 and PBE (min_lapw), I repeated the same parameters whenever
>> possible.
>>    The result is that after 200 iterations I did not get the
>> convergence with remarkable abrupt changes in ETEST during the
>> calculation.
>>    Please, let me show the steps I followed for the optimization and
>> take a look to see if there is any obvious mistake in the procedure:
>> 1) init_lapw (using the same parameter as in the previous
>> min_lapw-MSEC1-PBE optimization)
>> 2) create case.inm_vresp (from template)
>> 3) change NR2V to R2V in case.in0
>> 4) a short SCF cycle to create case.r2v
>> 5) change indxc to 28 in case.in0
>> 6) change indxc again to 50 and save the file as case.in0_grr
>> 7) a short SCF cycle (6 iterations ) with MSR1
>> 8) remove case.in0_grr
>> 9) change to MSR1a in case.inm
>> 10) finally  run_lapw -ec 0.000001 -fc 0.01 -in1orig -i 200 -it
>>    Probably you will say that the convergence parameters are too
>> strict, but I found them in a paper where a similar calculation where
>> performed (using pseudopotentials, not lapw).
>>    If you want, I can send you the files generated during the optimization.
>>    All the best,
>>                   Luis
>> PS: some atoms where fixed through case.inM
> --
> Professor Laurence Marks
> Department of Materials Science and Engineering
> Northwestern University
> www.numis.northwestern.edu 1-847-491-3996
> "Research is to see what everybody else has seen, and to think what
> nobody else has thought"
> Albert Szent-Gyorgi
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien

More information about the Wien mailing list