Investigation of Exchange Energy Density Functional Accuracy for Interacting Molecules


We present a comparison of exchange-only interaction energies obtained using several standard exchange functionals in the generalized gradient approximation to Hartree−Fock results for interacting molecules. We observe that functionals with an enhancement factor using a 25 power dependence on the gradient of the density for large density gradients offer consistently better agreement with Hartree−Fock calculations than that of alternative functionals. We revisit the functional offering the closest agreement and recalculate it to include its exact large gradient dependence.

Journal of Chemical Theory and Computation