Sigma, pi, and delta wavefunction forms for the hydrogen molecule



Using variational Monte Carlo methods, we examine simple, explicitly-correlated trial wavefunction forms for the X1Σmath image, B1Σmath image, a3Σmath image, b3Σmath image, I1Πg, C1Πu, i3Πg, c3Πu, J1Δg, and j3Δg states of the hydrogen molecule. The energies produced by our best wavefunctions are slightly above the best values in the literature. When we combine our trial wavefunction forms with the generalized Feynman-Kac path integral method, our results are in excellent agreement with the best nonrelativistic values for these systems except for the I1Πg state. Our best energy for this state, −0.65951554(6), is lower by several microhartrees than that obtained by Wolniewicz [J Mol Spectrosc 1995, 169, 329]. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010