[Pw_forum] nscf run and dos.x - reg

[Jess Wellendorff]

1. For dos.x, yes you should do a nscf run with a denser k-point grid 
than you used for the scf calculation. Do not know pp.x.
2. You should use 'tetrahedra' for the nscf run.
3. if you used 'tetrahedra' for the nscf, you do not need to specify 
this in the dos.x calculation. The output dos file will be generated 
using the tetrahedron method.

Examples attached.

On 03/04/2016 07:07 AM, Athul M wrote:
>
> Hello everybody at the PW forum,
>
> I am Athul Muralidhar, a student from SRM University,India.I have just 
> started to learn PWScf and have certain doubts regarding the same.
>
> I am working on a fcc type TiH2 system, I constructed the unit cell 
> and relaxed the structure.
> Took the relaxed co ordinates and set up an scf run. They were running 
> fine.
>
> Here's where i got stuck, and some of my doubts are:
>
> 1.Should i run an nscf run before going for dos.x/pp.x ? (as this is 
> not the case in VASP)
>
> 2.If i run an nscf run, should the 'occupation' be 'tetrahedra' or the 
> same one as the scf run?
>
> 3. If i had used "tetrahedra' in 'occupation' in the nscf run, what 
> should i do to get a dos  and a pdos plot?
>
> Hope you guys can help,
>
> Thanks in advance for you time!
>
>
>
> - Athul Muralidhar,
> Student,SRM University
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum

-- 
Jess Wellendorff
Scientific Specialist
QuantumWise A/S
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Denmark

web:   www.quantumwise.com
email: jess.wellendorff at quantumwise.com
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&DOS
  outdir='PbS',
  prefix='calc',
  Emin=5.0, 
  Emax=15.0,
  DeltaE=0.02,
  fildos='PbS.dos',
/
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&CONTROL
  calculation='nscf',
  outdir='PbS',
  prefix='calc',
  pseudo_dir='.',
  verbosity='low',
/

&SYSTEM
  ibrav=2,
  celldm(1)=11.3594091741d0,
  nat=2,
  ntyp=2,
  ecutwfc=40.0d0,
  ecutrho=160.0d0,
  input_dft='PBE',
  occupations='tetrahedra',
/

&ELECTRONS
  diagonalization='david',
  conv_thr=1d-08,
  mixing_mode='plain',
  mixing_beta=0.700d0,
/

ATOMIC_SPECIES
  Pb 207.200000d0 Pb.UPF
  S 32.065000d0 S.UPF

ATOMIC_POSITIONS {alat}
  Pb   0.0000000000d0   0.0000000000d0   0.0000000000d0
  S    0.5000000000d0   0.5000000000d0   0.5000000000d0

K_POINTS {automatic}
  27 27 27 0 0 0
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&CONTROL
  calculation='scf',
  outdir='PbS',
  prefix='calc',
  pseudo_dir='.',
  verbosity='low',
/

&SYSTEM
  ibrav=2,
  celldm(1)=11.3594091741d0,
  nat=2,
  ntyp=2,
  ecutwfc=40.0d0,
  ecutrho=160.0d0,
  input_dft='PBE',
  occupations='fixed',
  nbnd=25,
/

&ELECTRONS
  diagonalization='david',
  conv_thr=1d-08,
  mixing_mode='plain',
  mixing_beta=0.700d0,
/

ATOMIC_SPECIES
  Pb 207.200000d0 Pb.UPF
  S 32.065000d0 S.UPF

ATOMIC_POSITIONS {alat}
  Pb   0.0000000000d0   0.0000000000d0   0.0000000000d0
  S    0.5000000000d0   0.5000000000d0   0.5000000000d0

K_POINTS {automatic}
  9 9 9 0 0 0