[gpaw-users] question regarding delta-scf in gpaw

[abhishek khetan]

Dear Thomas,
Thanks!! all questions answered!
Best
Abhishek

On Mon, Jun 27, 2016 at 8:58 PM, Thomas Olsen <tolsen at fysik.dtu.dk> wrote:

> Hi Abhishek
>
>
>
> >1) I want to understand how can I get the correct "n" for my system? My
> molecule is very very large and its not easy to just >guess into which
> orbitals the excitations will take place. Is there a way to determine this
> automatically? Can I just directly >choose it to be the 'n' which is the
> band index of the first unoccupied state ?
>
> I am not sure what you mean by "guess". You choose it yourself. If you
> want the Lumo you choose the first unoccupied state. If you want to excite
> into the Lumo+1 you choose the second unoccipied state and so on.
>
>
>
> >2) Whats the meaning of molecule  = [0,1]. Does this correspond to 'C'
> and 'O' in the tutorial? Does it mean I must use >molecule =
> [0,1,2,3,4....120] in my simulations ?
>
> Yes
> >3) Also further, on the page it seems that 'bands:-1' is always used in
> convergence. I wanted to >understand is this has got anything to do with
> leaving the last band of the occupies bands out of >convergence for lumo? I
> want to know this to understand, for e.g. I want the excitation energy to
> the
> >level above lumo, then should I use 'bands:-2'
> I am not sure, but you should just make sure that you converge the
> unoccupied states you excite to.
>
> BR
> /Thomas
>



-- 
MfG,
abhishek
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