[Wien] Sum of PDOSes doesn't give total DOS

[Cormac McGuinness]

There is also the interstitial DOS

Cormac

- Sorry - I should reply to the list - will send anyway


On Fri, 2008-05-02 at 15:25 +0100, David Holec wrote:
> Dear Wien2k users & developers,
> 
> I'm getting a bit puzzled by following problem: when I calculate total 
> DOS of a system using tetra, and at the same time calculate PDOS of that 
> system, the sum of DOSes does not add up to total DOS.
> 
> Let me be a bit more specific: I have a 4 atomic unit cell of AlN, 2 
> atoms being Al and two N. My assumption would be that when I use 
> following int-file
> 
> Title
>   -1.50 0.002 2.500 0.003   EMIN, DE, EMAX, Gauss-broadening(>de)
>      11                     NUMBER OF DOS-CASES specified below
>      0    1   total         atom, case=column in qtl-header, label
>      1    1   Atom1 tot
>      1    2   Atom1 s
>      1    3   Atom1 p
>      1    4   Atom1 pz
>      1    5   Atom1 px+py
>      2    1   Atom1 tot
>      2    2   Atom1 s
>      2    3   Atom1 p
>      2    4   Atom1 pz
>      2    5   Atom1 px+py
> 
> then it would hold e.g.:
> 
>    Atom1 tot + Atom2 tot = total
> 
> or:
> 
>    Atom1 s + Atom1 p = Atom1 tot
> 
> When I integrate the total DOS (column 2 of the output corresponding to 
> the above tetra input) over -20eV to 0eV, I got 16.004e which is very 
> close to 16e I am expecting in the in this region (I am basically 
> missing 4*2 1s electrons which are deeper than my energy window). But 
> the same integral for Atom1 tot (column 3 in the output) gives 1.4285e 
> whereas for Atom2 tot (column 8 in the output) it gives 8.5117e. Their 
> sum is 9.9404e...
> 
> I assume it is tricky to try to distinguish which electron belongs to 
> which atom in solid state but still I would expect that the sum of these 
> two would be give the total DOS.
> 
> Could any help me either how to get out of this (can I simply 
> renormalise the PDOSes in order to get correct number of electrons?) or 
> tell me where my thinking goes wrong?
> 
> Many thanks in advance,
> David
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-- 
Dr. Cormac McGuinness, PhD. etc., Lecturer, School of Physics,
Trinity College, Dublin 2, Ireland. Cormac.McGuinness at tcd.ie
Telephone: +353 1 8963547 Fax: +353 1 6711759 Office: SNIAM 3.17