[Pw_forum] smoothing PDOS issue (QE 5.0.2)

[Paolo Giannozzi]

On Sat, 2013-04-27 at 18:19 +0200, David Grifith wrote:

> "   Obsolete variables, ignored:
>     io_choice
>     smoothing   "

very obsolete: removed on 30 June 2004. "Smoothing" was in eV,
"degauss" is in Ry, so in case you are used to a jurassic 
version of QE, you just need to set degauss=smoothing/13.6058 
in order to have the same results as before. 

> overall the only way that I can make my PDOS graphs as smooth as DOS
> ones is reducing degauss value to 0.01 ! but in some cases that we
> study the proper value for degauss is 0.001 and reducing it we may
> miss something. mightn't it ? 

your definition of "reducing" is not the same I use: "reducing" =
"making it smaller". Anyway: the broadening you need for scf
calculations is not necessarily the same you need for PDOS. 
You can safely specify a different broadening for PDOS. It
will affect only the way your pictures look like.

> We are going to compare a large sets of PDOS and DOS graphs and prefer
> not to compare one graph with lots of singularities with the others
> that are too smooth. I appreciate your advice in advance. 

My advice is to look at the attached notes, look at the dos_gam routine
in PHonon/PH/matdyn.f90, implement PDOS with tetrahedra.

P.

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