Reliable frequency and Raman for some specific states.


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Just Got Here
Hi,

I'm a greenhand in using NWChem.

I have used other programs before and learned that the frequency calculation in some packages is not reliable for some states, such as those are neither the ground state under the a specific multiplicity nor excited states which can be handled by TD-DFT methord. It's said the problem origins from the perturbation algorithm, where the lower energy wavefunction could be seen and thus introduce their influence into the results.

In NWChem, there are technics such as CDFT which can obtain some states as described above. Or say, an closed-shell state given the ground state is a broken symmetry state. I wonder can I get reliable frequency and Raman for these states in NWChem?

Thanks for you help.

Best regards.