[Pw_forum] occupations from input

[Lorenzo Paulatto]

In data 14 settembre 2009 alle ore 12:55:38, sreekar guddeti  
<colonel.sreekar at gmail.com> ha scritto:
> is it necessary to generate a new pseudopotential corresponding to the  
> new occupations because the example doesnt do so.

Hi Srekar,
which example are you talking about?

> it uses Al pseudopotential
> corresponding to occupations
> nl  l   occ
> 3S  0  2.00
> 3P  1  1.00
> 3D  2  0.00

that's correct

>
> 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

There is some error here: the upper line specify 6 occupations (6 spin-up  
bands) while the lower one only specifies 4 bands, but the number of  
spin-up and spin-down bands must be equal! Furthermore you have a total of  
6 electrons, which is twice as much as the Al atom.

If you don't specify nbnd you'll have 2 bands, and you'll have to specify  
2 occupations for spin-up and 2 for spin-down. If you have manually set  
nbnd to any other number (I would use at least 4), you'll have to specify  
that many occupations (of course the higher ones will be zero).

Best regards


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Lorenzo Paulatto
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