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How do I calculate electronic transitions

Posted: Wed May 30, 2007 6:40 pm
by stern
I would like to calculate all the electronic transitions for the first, say, 10 excited states. I am very new to VASP, but in GAMESS this is easily accomplished with a configuration interaction calculation. Is this possible? Also, I am not sure what the best KPOINTS choice is. I have a simple monoclinic system with about 88 atoms in the unit cell.

How do I calculate electronic transitions

Posted: Thu May 31, 2007 11:35 am
by admin
VASP(rel. 4.6) is based on DFT, which is a ground state theory (other than CI/HF), therefore any information about excited states has to be taken with care.
KPOINTS has to be converged, as for all bulk calcutations (for the ground state as well), please check E vs k-mesh (with a Monkhurst-Pack mesh).
In principle, occupancies can be set explicitelty in VASP by setting FERWE (please have a look in the manual), however, please mind the transition momentum selection rules if you do this.