RHF triplets CCEOM


I am curious about the flag RHF_TRIPLETS as TRUE.
How this work for CCEOM calculations?

Best regards,

Alan Guilherme Falkowski.

I don’t think this flag actually does anything, does it @Rollin_King?


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I did a little testing with tests/cc22. If you set reference rohf, then you will get triplet states too, along with singlets. Indeed the rhf_triplets appears not to work anymore. It’s original intention was to allow for triplets even if the underlying scf was explicitly RHF. (In that event, the excitations are explicitly spin-adapted singlet excitations.) Probably not a problem simply to run whole calculation rohf even if closed-shell.

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Thank you @crawdad and @Rollin_King.
I will test EOM-CC3 calculations with ROHF. I performed EOM-CC3 with the reference UHF to get triplets, but the calculation is very slow comparing to the RHF, maybe because of the extra matrix elements to be calculated.

Best regards.