[Pw_forum] Problem with newly implemented LDA -1/2 in atomic code (ld1)

[Nicola Marzari]

Hi,

If I understand correctly, you generated a lda-1/2 pseudo
with the atomic code, but did a lda calculation on silicon
with pwscf - so you will have gotten very similar but not perfectly 
identical results, of lda bulk silicon done with a consistent
pseudo (lda) or an inconsistent pseudo .

2) not sure if lda-1/2 is in pwscf (I think not) or if it
can be applied to solids.

			nicola



On 3/29/11 3:28 PM, Rajan Pandey wrote:
> Dear Quantum Espresso Community,
>
> I built the latest release (perhaps alpha) of QE-4.3a. Tried to look
> into the latest LDA -1/2 (assumed to be similar to SIC) in atomic code
> (ld1), and from the available test case of Silicon,
> I decided to check if I get a corrected band gap of bulk Si (from
> example05). First I generated LDA - 0.5 pseudo (input deck for the same
> is supplied with the distribution). Subsequently,
> to run a band structure calculation of Si, I used the template in
> example05. First I did band structure calculation with Si.pz-vbc.UPF,
> and then another calculation with the LDA - 0.5 pseudo (Si.LDA.0.5.UPF).
> I checked the output of scf calculation of the latter (I am copying the
> portion from output):
>
>
>       PseudoPot. # 1 for Si read from file Si.LDA.0.5.UPF
>       MD5 check sum: ac6493edff0fd6b486246c8fa11d17dc
>       Pseudo is Norm-conserving, Zval =  4.0
>       Generated using LDA-1/2 implemented by Leonardo Matheus Marion Jorge
>       Using radial grid of  431 points,  2 beta functions with:
>                  l(1) =   0
>                  l(2) =   1
>
>       atomic species   valence    mass     pseudopotential
>          Si             4.00    28.08600     Si( 1.00)
>
>       48 Sym.Ops. (with inversion)
>
> However, the end results of the two calculations are the same. That is
> the band structure and hence the band gap in two cases are same - nearly
> 50% underestimated.
> Not sure if I am missing something. I have attached the two scripts:
> run_example-0 ==> uses LDA pseudo, and run_example ==> uses LDA - 1/2
> pseudo.
> I shall appreciate any suggestion.
>
> Thanks, and regards,
>
> Rajan
>
-- 
----------------------------------------------------------------------
Prof Nicola Marzari    Department of Materials    University of Oxford
Chair of Materials Modelling  Director, Materials Modelling Laboratory
nicola.marzari at materials.ox.ac.uk     http://mml.materials.ox.ac.uk/NM