Application of the extended geminal theory to the BH molecule

Abstract

Extended geminal theory is applied to the ground state of BH at R=2.329 bohr. It is found that the inclusion of only “one-electron transfer” configurations leads to a lowering in the energy of ∼0.01 hartree, compared to the antisymmetrized geminal product wavefunction. This improvement is >90% of that achieved by a full configuration-interaction wavefunction. A “contracted” doublezeta basis set is also found to be quite good.