[Pw_forum] DOS calculation

[Stefano de Gironcoli]

the file ni.dos in example08 contains four columns; they are:
#  E (eV)   dosup(E)     dosdw(E)   Int dos(E)
and are computed according to the tetrahedron method

the file ni.pdos_tot contains  5 columns, they are
# E (eV)  dosup(E)   dosdw(E)  pdosup(E)  pdosdw(E)
and are computed by
 Gaussian broadening (read from input): ngauss,degauss=   1    0.020000
 
dosup/dw in the two files should be the same except for the
different way they are computed. Tetrahedra give nicer plot,
broadening gives more wiggly courves unless very many k-points are
used  (not the case in the example) but basic features are the same.

pdosup/dw are the sum of  atomic-wfc projected dos.
they agree with dosup/dw for energy where the atomic wfcs are a good
approximate basis set (tipically low lying states), they start to disagree
at higher energies (usually somewhere above Fermi energy)

stefano de Gironcoli

Yansun Yao wrote:

>Dear PWscf users
>       It might be a silly question. I got confused by the output of the DOS
>calculation in example08. Is the DOS in file .dos should be equivenlent to the
>total projected DOS in file .pdos_total, or the sum of all projected DOS? I
>found that the larger the energy is , the more apparent the discrepancy is.
>Why?
>       Thank you in advance!
>                              Yansun Yao
>
>
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