[CPMD-list] Absorption spectra

[Juerg Hutter]

Hi

> Dear All,
>
> I need to calculate absorption spectra for a molecule. The way it is
> usually done is to optimize the geometry in the ground electronic state
> and then calculate single point energy in several lower excited states
> on the optimized S0 geometry.

This is exactly what you can do in CPMD. You first perform a ground state
calculation at a given geometry and follow that with a TDDFT calculation
of N excited states. If you add the calculated excitation energies to
the ground state energy you get the total energy of the excited states.

regards

Juerg Hutter


According to my knowledge CPMD does not
> implement single point calculation (OPTIMIZE WAVEFUNCTION) in excited
> states (TDDFT) - am I right ? If so, please advise if the following is a
> good workaround: run OPTIMIZE GEOMETRY in excited state with very high
> (say 1.D0) CONVERGENCE GEOMETRY criterion and take the ETOT energy as
> the single point energy in excited state ?
>
> Thanks and regards,
> Lukasz Walewski
>
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