Study of the Rydberg States of H2

Abstract

In this paper we apply a formalism based on an effective one‐electron Hamiltonian to the Rydberg states of H₂. It is assumed that the core can be represented by the ground‐state wavefunction of H₂⁺. The energies of the ³Σ_g, ³Σ_u, ¹Σ_u, ³Π_u, and ¹Π_u states have been calculated at R_AB=2.0 a.u. The good agreement between theory and experiment obtained for the ³Σ_g, ³Σ_u, ³Π_u, and ¹Π_u states indicates that the frozen‐core approximation gives an accurate description of these states. We examine the discrepancy between theory and experiment in the case of the ¹Σ_u states and suggest a criterion to determine the applicability of the frozen‐core approximation to Rydberg states of diatomic molecules.