I don't think this is currently possible so I guess this counts as a feature request.
Is there currently any way to use the RVS (restricted virtual space) approximation with either CC2 or ADC(2) for calculating excited states? I've got some situations where TDDFT is possibly a bit questionable (large amounts of charge-transfer character to electronic transitions) but CC2 and ADC(2) are just out of reach with the systems I'm interested in...although they may be if it were possible to
Essentially, it allows a cutoff to be set (typically, 50 or 60 eV), above which virtual orbitals are not included in the coupled-cluster calculations, although clearly it's only of any use for the lowest excited states.
I think it's possible to do similar to some extent through FNOCC, using suitable values of OCC_PERCENTAGE or OCC_TOLERANCE, but I don't think it's possible with CC2 or ADC(2). It looks something that would be easy to incorporate but that's probably down to my naivety of the code / algorithms!
E.g. CC2 lit: J. Chem. Phys. 134, 214114 (2011)
ADC(2) lit: J. Comput. Chem. (2017)