The liH2+ quasimolecule. a comparison between the configuration interaction and the OEDM approaches

L.F. Errea , L. Méndez , A. Riera , M. Yáñez , J. Hanssen , C. Harel , A. Salin

We present a direct comparison of the One-Electron Diatomic Molecule (OEDM) method with the conventional molecular approach, based on a full-configuration-interaction (CI) method using a basis set made up of symmetry adapted anti-symmetrized products of Gaussian type orbitals (GTO), for the treatment of atomic collisions involving two-electrons. The quasimolecule LiH2+ has been chosen as an example. We have studied the advantage of a screened Hamiltonian to define the OEDM orbitals. The energy correlation diagrams for the singlet and triplet subsystems are discussed, and also the physical character of the molecular states involved in the Li2+(1s)+H(1s) collision. We show that the comparison between both methods permits to interpret the detailed behaviour of the couplings obtained in the full configuration interaction method and to assign unambiguously molecular symbols in the correlation diagrams. Even though the intuitive « one active electron » picture is useful for the present collision system, the inner-outer orbital interaction is shown to be significant for both the energy diagram and couplings.

Mots clés: atom ion collisions; hydrogen neutral atoms; lithium; molecular electron correlations; molecular orbitals calculations; quasimolecules

Domaines: Articles anciens

L.F. Errea, L. Méndez, A. Riera, M. Yáñez, J. Hanssen, et al.. The liH2+ quasimolecule. a comparison between the configuration interaction and the OEDM approaches. Journal de Physique, 1985, 46 (5), pp.709-718. ⟨10.1051/jphys:01985004605070900⟩. ⟨jpa-00210012⟩