Density Fit CCSD(T) with UHF reference?

1

When I try to run CCSD(T) with a uhf reference I get the error message:

select_ccsd_t_: Method ‘ccsd(t)’ with CC_TYPE ‘DF’ and REFERENCE ‘UHF’ not available

I was wondering if there’s any simple fix to this, since I’m running calculations that are too expensive for conventional CCSD(T). For some reason both Psi4 and ORCA don’t seem to allow this.

2

You can find an overview of available implementations here: http://psicode.org/psi4manual/master/notes_c.html#alternate-implementations

Unfortunately, open-shell DF-CCSD(T) is not available.

orca should have CC algorithms with UHF other than the MO one. Also open-shell DLPNO since the new version (though read the manual about it!)