I suspect that roughly what’s going on is as follows.
oeprop() is the unified properties interface for most methods where the density is about as cheap as the energy. Then there’s coupled cluster, where one has to solve the lambda equations, doubling the cost. In order to drive this, CC properties should be accessed through
On point 1, oeprop after energy is probably using HF, which is the most recent available density. Is there a label near the properties printout? We put that in to try to avert misinterpretation. Especially for CC, you’ll need a gradient-level calc for properties.
On point 3, Cfour is wonderfully able when it comes to CC higher excitations and properties. They do have CCSD(T) quadrupoles and octopoles, whereas Psi4 only has CCSD and only through quadrupole.
The people closer to the CC code can correct me on any of these points. @amjames @robertodr