Exponent optimization for ? states of H2

Abstract

The total energy of the lowest 1 Π u, 3 Π u, 1 Π g, 3 Π g states of H2 was minimized in an extended Hartree-Fock procedure employing a double configuration wavefunction. The exponents of the basis functions 1s, 2s, 2pσ, 2pπ, 3dπ were optimized separately for all four states at various internuclear distances. The results show that the exponents are strongly state and distance dependent. They cannot be generally represented by atomic or equilibrium values. The details of the optimization process are presented.