[Pw_forum] LDA+U and occupations matrix problems / call for NC PP Cu & Co

[Stefano de Gironcoli]

Dear  Ricardo Faccio,
The problem of normalization of atomic wavefunctions in LDA+U should 
have been solved about one year ago in the cvs version and incorporated 
in recent distributions. I include below the CVS log message of that 
correction that should clarify the change.
It should be possible to repeat your calculations without the 
norm-atomic flag on and atomic wavefunctions should be renormalized  on 
the atomic grid, that is in a configuration independent way, hence 
forces and stress should be ok).
Please report any problem that you may experience,
best,
   stefano
>
> date: 2008/07/14 21:50:33;  author: degironc;  state: Exp;  lines: +84 -0
> Normalization of atomic wavefuncitons is checked (only for those with
> non-negative occupation) after pseudopotential reading and if it found to
> be different from 1 by more than 1.d-6 the wavefunction is renormalized.
>
> Should make no difference in all usual cases since atomic wfcs are only
> used in order to generate the initial set of trial wfcs and normalization
> is not important there...
>
> It is VERY important for LDA+U calculations using atomic wfc in the 
> progector
> (the default case) since proper normalization is assumed and lack of 
> it leads
> to disasters.
>
> Hopefully this will solve many of the difficulties people have encounterd
> when using LDA+U with older RRKJ pseudopotentials, where normalization
> was not imposed properly (and nobody realizes except when doing LDA+U) or
> pseudopotentials of unknown origin.





Ricardo Faccio wrote:
> Dear Pwscf users
>
> I'm a newbie using pwscf, and I’m trying to reproduce some full-potential 
> all-electrons results from a previous work using WIEN2k. My system is a 
> cuprate/colbatite YBaCuCoO5. I succeed running the lda+u calculations, but I 
> found the previous discussed problem regarding the lack of normalization in 
> some PP (non norm-conserving). I worked with the UPF's files from the QE web 
> page: Cu.pbe-d-rrkjus.UPF and Co.pbe-nd-rrkjus.UPF.  The problem of 
> occupations higher than 1 was resolved with the flag: U_projection_type = 
> 'norm-atomic'. But I am interested in checking the stresses and forces, in 
> order to verify my previous equilibrium solution and these are not 
> implemented for such correction ('norm-atomic').
>
> For these reason I would like to ask you for a PBE-Norm-conserving PP for Cu 
> and Co, if anyone has it available. I think this is the fattest solution in 
> order to avoid the U dependency upon normalization (through 
> U_projection_type) and for checking my previous results. But, if I have no 
> answers, I will try to generate these files from myself (but it is a little 
> bit more complicated that ATOMS implemented in SIESTA).
>
> Thanks in advance and sorry for the inconvenience.
>
> Ricardo Faccio
>
> -------------------------------------------------------------------------
>   Dr. Ricardo Faccio
>   Prof. Adjunto de Física
>   Mail: Cryssmat-Lab., Cátedra de Física, DETEMA
>   Facultad de Química, Universidad de la República
>        Av. Gral. Flores 2124, C.C. 1157
>        C.P. 11800, Montevideo, Uruguay.
>   E-mail: rfaccio at fq.edu.uy
>   Phone: 598 2 924 98 59
>               598 2 929 06 48
>   Fax:    598 2 9241906
>   Web:  http://cryssmat.fq.edu.uy/ricardo/ricardo.htm
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>