Is there a way to run restricted open-shell DFT in Psi4? I know you're not really supposed to run RODFT, but it would be useful to be able to initialize open-shell CAS calculations with a KS reference.
Sure, its pretty easily done if you look at libscf_solver/rhf.cc and libscf_sovler/rohf.cc. I don't think this will be a supported feature however as in the general case this operation does not make much sense due to the needed divergence of near-nuclear spin densities.
The interesting thing is that ROKS is a partly valid option, e.g. in psi4/driver/procrouting/proc.py:
elif core.get_option('SCF', 'REFERENCE') in ['ROHF', 'ROKS', 'UHF', 'UKS']:
core.set_local_option('SCF', 'GUESS', 'GWH')