[DFTB-Plus-User] pdos for different atoms but with same coordinates

[Bálint Aradi]

Dear Ariel,

>    In my system, it has two parts, TiO2 and an organic molecule, in both parts they have same oxygen atom, I want to make pdos calculation to seperate the two parts.
> But the DFTB PDOS can only allow for regions where all atoms belong to the same species, so I marked the same species in my following input file, Atoms = 141:652, represent the oxygen in TiO2 system, showing as Label = "dos_o"; Atoms = 653:656, represent the oxygen in the organic molecule, showing as Label = "dos_o1",
> however, the results showed with the same ouput infornation in every dos_xx.xx.dat file, that is obvious inaccurate.
> I am wondering how can I get pdos for each atom, especially to get the pdos of TiO2 system, exclusive the oxygen in the organic part.

It is only for the shell-resolved PDOS, that DFTB refuses regions
containing different species. (If somebody asks for the PDOS on the
s-shells of O and Ti together, it is most probably a mistake, so the
program stops.) For non-shell resolved regions, you can have any type of
atoms in your region.

Plesae note, that every Region{} specification is read on its own,
*independent* from all others. So your input

   Region {
     Atoms = O
     ShellResolved = Yes
     Label = "dos_o"
   }
   Region {
     Atoms = 653:656
   }
   Region {
     Atoms = O
     ShellResolved = Yes
     Label = "dos_o1"
   }

creates one region with all O atoms in your system, one region with
atoms 653-656 and finally one region again with all O atoms in your
system. Therefore, the information you get for the first and the last
one will be identical.

In order to get a shell resolved PDOS for all O atoms within a given
region, you will have to specify all those atoms by their number, there
is unfortunately no shorthand notation for it so far.

    Region {
      Atoms {
        1 3 5 7 12 433 # Put the sequential number of all atoms you want
       }
       ShellResolved = Yes
       Label = "dos_o1"
    }

  Best regards,

  Bálint



-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b_aradi/


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