Unfortunately not. There was some ability to accept user-defined guess vectors for EOM in PSI3. However, that was before my time so I don’t how well it worked, I just know that the code to read them is still around in the source for the EOM code, but all of the calls to it have been removed, because it required functionality from PSI3 that never made it into psi4.
To attempt to capture these missed states here are a few things you can try (have not tried this myself so mileage may vary)
- The EOM-CCSD Roots which are used to seed the EOM-CC3 iterations, are themselves seeded by CIS roots which are seeded by a guess generated by single excitations between (HOMO-1, HOMO, LUMO, LUMO+1). You can expand the CIS guess by increasing the
EXCITATION_RANGE options. The default value is 2.
- In the same spirit as above you can expand the search at the CC3 level by looking for more roots than you need to find. Unfortunately there is no way to simply change the number of CCSD roots that will be fed as guesses to the CC3 iterations, so to start the search with a larger guess space you will need to look for more roots which will take significantly longer at the CC3 level since roots are found one at a time.
Customization of the EOM guess would be a useful feature though, and is something which is on our radar. However we don’t currently have anyone working on it.
Given your use case you might want to consider using QCHEM (if you have it/can get it) as they have a wide range of options that the user can use to tune EOM-CC calculations, or CFOUR where EOM-CC has been implemented up to full quadruples.
Sorry if this is not very helpful.