Hello,
There is anyway to compute the transition quadrupole moments between the ground state and excited states?
Best regards.
With what method?
A quick survey of the code says this is currently supported with CI-type methods, but it should be straightforward to add to other methods that support transition dipoles.
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Thank you. With CI-type methods or EOM-CC. I didn’t find these documentations. Could you send here, please?
Do you know how to search Psi4’s examples? fci-tdm, fci-tdm-2, and ci-property are going to be your starting points for CI-type methods. Naturally, these are computed using the expectation value formalism, not the response formalism.
A quick check indicates that while EOM-CC has all the information it needs to compute transition quadrupoles, it doesn’t. (@crawdad, can you confirm?) On the technical side, the core of the issue is that our quadrupole computation code is in oeprop, which cceom doesn’t use for historical reasons. Addressing that would be less straightforward than I thought.
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That’s correct that the EOM-CC code cannot compute quadrupole transition moments, but the changes to cceom to allow that would be straightforward for someone who has the time and inclination. 
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I have the inclination, just not the time right now. 
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