Dispersion for Hartree Fock

How To
#1

Is there a way to get dispersion for Hartree Fock (not DFT) calculations? All I could find in the manual were DFT-D methods.

#2

EMPIRICAL_DISPERSION = TRUE works with Hartree-Fock, I have used HF+D3 in several papers.

#3

Thanks for the tip! I’ll give it a try.

#4

Along the same lines, you might consider the HF-3c approach (METHOD = HF-3C and BASIS = MINIX), which is semiempirical but works well for structures, is not totally unreasonable for non-covalent interaction energies, and is based on a minimal basis set so is very fast. It was parameterized specifically for use with this particular basis set so Q-Chem will generate a warning (though will not terminate) if you try to use HF-3c with any other basis set.

#5 
    EMPIRICAL_DISPERSION = TRUE
    DFT_D   D3

Works like a champ.

Thanks again.