[Pw_forum] How to calculate DOS at the Fermi Energy?

[Paolo Giannozzi]

On Apr 13, 2011, at 10:37 , r s wrote:

> running of the pw.x code with following document as input file:
> [...]
>     occupations='smearing', smearing= 'mp', degauss= 0.02 ,
> [...]
> and then, running of the pw.x code with tetrahedra occupation:
> [...]
> for calculation of total Dos, running of the dos.x code with below  
> text:
> [...]
> now for calculation of density of state at fermi energy, i call  
> pp.x code with following input file:
> [...]
> but after running, the code says:
> [...]
> from local_dos : error #     1
> guassian broadening needed

first of all: it says "gaussian broadening needed". Error message may  
not be optimally
clear, but they are not misspelled, usually.

pp.x reads the data file produced by the second pw.x run, which  
overwrites the contents
of the data file written in the first pw.x run. So pp.x sees  
tetrahedra and tetrahedra are
not implemented for the calculation of local dos. The value of the  
gaussian broadening
taken in input by dos.x is used by dos.x and cannot propagate to  
other codes (dos.x
does not change the data file produced by pw.x). By the way: it  
doesn't make sense to
perform calculations with tetrahedra (useful for DOS) and throw the  
results away by
using gaussian broadening for DOS

P.
---
Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222