Pseudopotential Theory of Atomic and Molecular Rydberg States

Abstract

In this paper we present a description of atomic and molecular Rydberg states using an effective Hamiltonian in the one-electron Hartree—Fock approximation. A pseudopotential is introduced to ensure the orthogonality of the Rydberg orbitals to the core. The core is represented by the ground-state wavefunction of the corresponding positive ion. In order to incorporate the pseudopotential formalism in a description of Rydberg states, the original pseudopotential theory is extended to the case where the core and valence orbitals are eigenfunctions of different one-electron operators. The formalism is applied to the triplet S states of helium and beryllium atoms and the results of numerical calculations are given. Good agreement with experiment is found. Possible extensions of the theory to more complex systems are discussed.