[Wien] Problem optimizing internal parameters NN - error

[jiang@fhi-berlin.mpg.de]

Hi Bo,
I think the problem in your calculations is probably caused by too small RMT
values in the struct file. The muffin-tin spheres should never overlap
when you optimize the structure. Try reducing RMT value a little bit to
see what happens.

Good luck!

   Hong

> Dear Wien2k users and developers,
>
> I'm a new user and I've been struggling with this problem and find no way
> out for several days and I'm really in despair. I sincerely request for
> your
> help as my last hope, thanks a lot!
>
> The problem is that:
> When I'm trying to do the optimization with the example TiO2 and try to
> optimize its atomic positions using min_lapw. Firstly I tried to follow
> the
> userguide in ch 10.3 exactly using w2web, and run scf first. As pointed in
> the userguide, the last force was a jump. Then I proceeded to mini
> positions, however, first of all, before every min_lapw round there is a
> warning saying:
>
> WARNING: Step size reduced due to overlapping spheres -- check RMT
>
> after several (around 10) rounds, PORT crashed:
>
>>>  (mini) PORT stopped -> exit
>  :WARNING you might have inconsistent Forces/Energies
>
> The last few lines on FGL002 inside *mini are (FGL001 is alway zero):
>
> :FGL002:   2.ATOM               -45.621114095   -45.621114095
> 0.000000000 t
> :FGL002:   2.ATOM               -45.586465863   -45.586465863
> 0.000000000 t
> :FGL002:   2.ATOM               -45.575859262   -45.575859262
> 0.000000000 t
>
> Then I removed case.tmpM and modified case.inM as
>
> NEW1 2.0 0.35      # PORT/NEWT;  tolf, Initial Trust Radius
> 0.0 0.0 0.0 1.0   #Atom  1 Generated by pairhess
> 1.0 1.0 0.0 1.0   #Atom  2 Generated by pairhess
>
> Then rerun min_lapw using w2web
>
> however, this time, in the first round, after 4 cycles I get it
> crashed with NN -Error:
>
> in cycle 4    ETEST: 0   CTEST: 0
>  LAPW0 END
>  LAPW1 END
>  LAPW2 END
>  CORE  END
>  MIXER END
> ec cc and fc_conv 1 1 1
>
>>   stop
> NN - Error
>
> The version used: Wien2k_07, compiler ifort, mkl 9.1, in series mode
>
> Could you please help me? Thank you very much!!! If any more information
> needed, please let me know, thanks!
>
> --
> Thanks and Best Wishes.
>
> Sincerely yours,
> Bo Qiu
>
> http://web.ics.purdue.edu/~qiub/ <http://web.ics.purdue.edu/%7Eqiub/>
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