[Pw_forum] something about Pt.pw91-n-van.UPF

[Eyvaz Isaev]

Dear Vega,

How about occupations (smearing or tetrahedra) keyword for Pt which is metallic? As there is no "occupations", obviously, your system is considerd as a semiconducting, and there is no way to improve the convergence adding more bands, as all the bands higher than 
e(n_valence_electrons/2) are considered as empty bands. And you were quite lucky to avoid the message like "metallic system, specify occupations", because the PsP used 10 valence electrons.

In this respect your results seem to be incorrect. 

Bests,
Eyvaz.
P.S. As you used Pt atom in a large box, of course, you should apply only a smearing technique (your favorite). 


-------------------------------------------------------------------
Prof. Eyvaz Isaev, 
Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, 
Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden 
Condensed Matter Theory Group, Uppsala University, Sweden 
Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se, eyvaz_isaev at yahoo.com


--- On Fri, 1/30/09, vega lew <quantumdft at gmail.com> wrote:

> From: vega lew <quantumdft at gmail.com>
> Subject: [Pw_forum] something about Pt.pw91-n-van.UPF
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Date: Friday, January 30, 2009, 7:14 PM
> Dear all
> 
> i have a question about the pseudo potential of
> Pt.pw91-n-van.UPF.
> 
> When I want to calculate the total energy of Pt atom in a
> large box, the
> calculation could coverge. the box is consistent with the
> surface
> calculation. the calculated value of total energy in output
> file is
> -88.64000965 Ry which is a little different from the value,
> -88.64879046471
> Ry, in the Pt.pw91-n-van.UPF file. do you think the
> deviation is acceptable?
> 
> And when I add more empty band, two or three more, in the
> system using
> 'nbnd' command , the calculation can't coverge
> with 100 scf cycles. How do
> you think about it?
> 
> My input files as follows,
> 
> 
>  &CONTROL
> 
>                        title = 'Pt' ,
> 
>                  calculation = 'scf'
> ,
>                 restart_mode = 'from_scratch'
> ,
>                       outdir = '/tmp/' ,
>                       wfcdir = '/tmp/'
> ,
>                   pseudo_dir =
> '/home/vega/espresso-4.0/pseudo/' ,
>                       prefix = 'Pt' ,
> 
>                      disk_io = 'none'
> ,
>                        nstep = 1000
> ,
>  /
> 
>  &SYSTEM
> 
>                        ibrav =
> 8,
>                    celldm(1) =19.6144,
>                    celldm(2) = 1.0955,
>                    celldm(3) = 1.7218,
>                          nat =
> 1,
>                         ntyp =
> 1,
>                        nosym = .ture.
> ,
>                    ecutwfc   =   30,
>                    ecutrho   =  300,
>                         nbnd = 8,                     # or
> nbnd =7, the
> calculation can't converge for this two value
> /
> 
>  &ELECTRONS
> 
> 
> 
>  /
> 
>  &IONS
> 
> 
>  /
> 
> ATOMIC_SPECIES
> 
>    Pt  195.09000
> Pt.pw91-n-van.UPF
> ATOMIC_POSITIONS crystal
> Pt    0.68061   0.25139   0.40394     1     1     1
> K_POINTS gamma
> 
> thank you for reading
> 
> vega
> 
> -- 
> ==================================================================================
> Vega Lew ( weijia liu)
> PH.D Candidate in Chemical Engineering
> State Key Laboratory of Materials-oriented Chemical
> Engineering
> College of Chemistry and Chemical Engineering
> Nanjing University of Technology, 210009, Nanjing, Jiangsu,
> China
> ******************************************************************************************************************
> Email: vegalew at gmail.com
> Office: Room A705, Technical Innovation Building, Xinmofan
> Road 5#, Nanjing,
> Jiangsu, China
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