Long- and intermediate-range interaction between two ground state hydrogen atoms

Abstract

Perturbation theory in the polarization approximation has been employed, without using the multipole expansion for the interaction Hamiltonian, to calculate the second- and third-order interaction energies of two ground state hydrogen atoms for internuclear separations R - 4(2) 12 a.u. Using recently computed variational energies for H-H and H-H, the values of higher order corrections to the interaction energy have been estimated. The accuracy of several approximations commonly used in calculations of inter-molecular interaction energies has been tested.