High-spin states in tetrahedral X4 clusters (X = H, Li, Na, K)
Résumé
The high-spin electronic states for lithium, sodium, and potassium four-atom clusters were studied. In particular, we performed coupled cluster geometry optimization of the quintet state in tetrahedral geometry. The quintet state of these systems is characterized by having all the valence electron unpaired, giving rise to the so-called no-pair bonding. Single-point full configuration interaction computations on the equilibrium geometries for the various clusters are also presented. The analysis of the valence orbitals in a localized representation confirms the importance of the p atomic orbitals to explain this unusual type of bond.