AbstractThe slow computational speed of the generalized valence bond perfect pairing method (GVB‐PP) has been an impediment to its routine use. We have addressed this problem by employing a diatomics in molecules Hamiltonian derived from a second quantization perturbation approach. This results in all three‐ and four‐centered two‐electron integrals being dropped from the traditional GVB‐PP calculation. For moderate sized molecules, as for example C20 computed with a double zeta + polarization basis, there is on average a fifty‐fold decrease in computational times. In this article, we present the theory behind our approach and analyze the accuracy and speed of this approximate GVB‐PP method for several cases where density functional methods have produced ambivalent results. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008