[Octopus-users] TD projections

[Alberto Castro]

Well, the obvious answer would be to take the Fourier transform. At
the moment octopus does not have any utility to take the Fourier
transform of the projections file, but you can just do it with any
external code suitable for that.

Alberto.

2010/4/13 Robertson Burgess <Robertson.Burgess at newcastle.edu.au>:
> Dear Octopus Users,
>
> I'm trying to analyse the source of various peaks within the optical absorption spectrum, which I am calculating using the explicit time-propagation method. I understand that it would be more straight forward to do this using the Casida method, as each peak can be directly attributed to an occupied/unoccupied pair of orbitals. However since I am calculating for large systems I am using the time-propagation method since it scales better. When I spoke to some people about this in Benasque last January I was told I could try using the TDOuput= td_occup to project the excitation peaks onto the ground-state wavefunctions, which could include some unoccupied orbitals. However when I did this I saw that the projections were given for each time-stamp. Is there some way to convert these time-dependant projections into frequency-dependant projections? That way they could be easily associated with individual peaks.
>
> Sincerely,
> Robertson Burgess
> University of Newcastle, Australia
>
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-- 
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Dr. Alberto Castro

Instituto de Biocomputación y Física de Sistemas Complejos (BIFI),
Edificion I+D,
Mariano Esquillor Gómez s/n,
50018 Zaragoza, España.

Tel:   +34 976761000 (extension 5411)
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email: acastro at bifi.es
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