Abstract

Confinement and pressure have profound effects on the electronic structure of atoms and molecules. In this work, we study the effects of a harmonic confinement on the electronic structure of the lithium dimer. To do this, we use quantum chemistry methods that include much of the electronic correlation (Coupled Cluster and CASSCF). The confinement induces a change, with respect to the free molecule, in the electronic configuration of Li-2. There is a critical confinement value for which the ground state stops being the singlet 1 sigma g+ and becomes the triplet 3 sigma g-. We also study changes in the bonding pattern. Li-2 conserves the bonding pattern of the free molecule independently of the strength of confinement, as it is revealed by the electron localization function.