Near-ultraviolet emission bands of Li—rare-gas molecules

Near-ultraviolet emission bands have been observed in Li-Ar, Li-Kr, and Li-Xe mixtures. The bands are due to transitions from bound molecular Li---rare-gas states associated with the atomic Li $3d$, $3p$, and $3s$ states and ground-state rare-gas atoms. The transitions are all to the dissociative Li---rare-gas 2sσ molecular ground state. The Li-Ar, Li-Kr, and Li-Xe 3sσ-2sσ collision-induced bands are progressively shifted, for the heavier rare gases, further to the red of the asymptotic atomic Li 3s-2s energy difference. For Li-Xe this shift is a remarkable 4000 cm^-1. We also report rate coefficients for quenching, by all the rare gases, of the atomic Li $3d$ and $3p$ states.