[Wien] Convergence Problem

[Peter Blaha]

Please check the relevant quantity. For a mbj calculation this is 
usually the gap.

grep :GAP case.scf

Is it converged and stable ?

Also monitor   :DIS how it changes (smooth or with jumps or with 
long-term slow oszillations?), which may give further hints.

mBJ calculations sometimes converge quite difficult, because the kinetic 
energy density (tausum) is mixed separately using PRATT and the density 
mixing (using MSR1) may be confused because it does not know about the 
tausum. In addition there is a "3rd mixing" in lapw0 (potential mixing, 
which depends on the "greed" of the last cycle - which cannot be changed 
by an input)

Sometimes it helps to:

i)  change the mixing factor in case.inm_tau  ( even larger when 
convergence is slow but smooth, smaller when oszillating !)

ii) change for a couple of iterations (maybe 20) to PRATT in case.inm, 
then continue again with MSR1


Am 25.04.2023 um 11:01 schrieb Hülya Gürçay:
>  Dear Prof. Dr. Blaha and WIEN2k users,
>
> I've been using Wien2k since 4 months. I am a physics master's 
> student, calculating the magnetic and thermoelectric properties of 
> quaternary Heusler compounds. I have a question,
>
> Energy and charge converged with PBEsol but not with PBEsol-mbj 
> potential .
>
> Xc potential : PBEsol - mbj
> cc: 0.0001
> ec: 0.00001
> kmesh:20,20,20
>
> Below I am sharing the results got after 100, 150 and 200 iterations.
>
>     cycle 100 <>(Sat Apr 22 21:59:29 +03 2023) >(1/99 to go)
> :ENERGY convergence:  0 0.00001 .0001018050000000
> :CHARGE convergence:  0 0.0001 .0079100
> >   energy in SCF NOT CONVERGED
> >   stop
>
>     cycle 150 <>(Sat Apr 22 23:24:49 +03 2023) >(1/49 to go)
> :ENERGY convergence:  1 0.00001 .0000068950000000
> :CHARGE convergence:  0 0.0001 .0032008
> >   charge in SCF NOT CONVERGED
> >   stop
>
>     cyle 200 <>(Sun Apr 23 00:47:57 +03 2023) >(1/98 to go)
> :ENERGY convergence:  1 0.00001 .0000027900000000
> :CHARGE convergence:  0 0.0001 .0021041
> >   charge in SCF NOT CONVERGED
> >   stop
>
> What should I do to get convergence? Please give your valuable suggestions
>
> BestRegards,
> Hülya
>
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-- 
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Peter Blaha,  Inst. f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-158801165300
Email:peter.blaha at tuwien.ac.at           
WWW:http://www.imc.tuwien.ac.at       WIEN2k:http://www.wien2k.at
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