Infrared spectra, structure and bonding in the LiO₂, LiO₂Li, LiO and Li₂O molecules in solid neon

Laser-ablated lithium atoms react with oxygen molecules, as do thermal lithium atoms, to form the LiO2 and LiO2Li ionic molecules. In addition excess energy associated with the laser ablation process fosters the endothermic reaction to give LiO and ultimately Li2O, which form in higher yield from the analogous N2O reactions. The subject molecules were trapped in solid neon and identified by isotopic shifts, comparison with earlier argon and nitrogen matrix results, and DFT frequency calculations. The observed neon–argon matrix shifts follow the molecular polarities. Molecular orbitals from theoretical analysis show the highly ionic nature of the electron distribution in the LiO2 and LiO2Li molecules.