Tiny mixing parameters? RE: [Wien] Ghost band come from large charge fluctuation

[Torsten Andersen]

Dear Kevin,

not being an expert in "mixer", I nevertheless believe I have understood 
the general concept, and I would say that with such a tiny mixing 
parameter one will end up (very very slowly) in the nearest LOCAL 
minimum and very likely miss the global minimum if local minima exist 
between the output of dstart and the "true" ground state.

Best regards,
Torsten.

Jorissen Kevin wrote:
> I would really like to have the specialist's opinion on this (LD Marks?) : is there any sense in using mixing parameters of 10^-6 ?
>  
> Kevin Jorissen
>  
> EMAT - Electron Microscopy for Materials Science   (http://webhost.ua.ac.be/emat/)
> Dept. of Physics
>  
> UA - Universiteit Antwerpen
> Groenenborgerlaan 171
> B-2020 Antwerpen
> Belgium
>  
> tel  +32 3 2653249
> fax + 32 3 2653257
> e-mail kevin.jorissen at ua.ac.be
>  
> 
> ________________________________
> 
> Van: wien-admin at zeus.theochem.tuwien.ac.at namens liyh
> Verzonden: do 10-3-2005 2:58
> Aan: wien at zeus.theochem.tuwien.ac.at
> Onderwerp: Re: [Wien] Ghost band come from large charge fluctuation
> 
> 
> 
> Thanks very much to Marks!
> There are still some problem not resolved.
> As to avoid the large charge fluctuation we set the mixing parameter to 0.000001 and using PRATT
> method, but this can not resolve the problem and we still meet a ghost band in the second iteration.
> these are the charge values from  *.scf file.
> 
>  
> 

-- 
Dr. Torsten Andersen        TA-web: http://deep.at/myspace/
AG Hübner, Department of Physics, Kaiserslautern University
http://cmt.physik.uni-kl.de    http://www.physik.uni-kl.de/

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