[Pw_forum] occupations from input

sreekar guddeti colonel.sreekar at gmail.com
Mon Sep 14 12:55:38 CEST 2009


Dear Sir Paulatto,
is it necessary to generate a new pseudopotential corresponding to the new
occupations because the example doesnt do so. it uses Al pseudopotential
corresponding to occupations
nl  l   occ
3S  0  2.00
3P  1  1.00
3D  2  0.00

whereas the occupations card reads
OCCUPATIONS
1.0 1.0 1.0 1.0 0.0 0.0
1.0 1/3 1/3 1/3

sincerely,
Sreekar Guddeti
BTech + MTech
Engineering Physics
IIT Bombay
India


> >  Can somebody clearly tell me how to define occupations from input. I
> cant
...
....
> It's quite easy, actually, there are only a couple of points you have to
> keep in mind:
>
> 1. if nspin=1 occupations can go from 0 to 2, you have to specify the
> occupation from the lower to the highest band and the sum of the
> occupations will have to be the number of electrons;
>
> 2. if nspin=2 occupations go from 0 to 1, you specify the occupation for
> spin up first, then for spin down (always on a newline);
>
> Let's say you want to reproduce the calculation of the Cr isolated atom,
> with semicore states in valence: 3s2 3p6 4s1 3d5 4p0
>
> first with nspin=1 and spherical (as it is done in ld1.x):
> OCCUPATIONS
>  2    2 2 2   1   1 1 1 1 1   0 0 0
> !3s2    3p6   4s1     3d5        4p0
>
> then spin polarized (nspin=2), according to Hund's rule you have to
> maximize the total angular momentum:
> OCCUPATIONS
>  1    1 1 1   1   1 1 1 1 1   0 0 0
>  1    1 1 1   0   0 0 0 0 0   0 0 0
> !3s2    3p6   4s1     3d5        4p0
>
....
-- 
Sreekar Guddeti
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