Knowledge Bank

Molecular potentials for the $X2\Sigma 1/2$ and $A2\Pi 3/2,1/2$ electronic states in sodium-rare gas diatomics are determined from the pressure dependence of normalized emission in the extreme red wing of the 5893 {\AA} sodium resonance lines perturbed by 1-600 Torr of rare gas. The quasistatic model of line broadening is used to relate the pressure dependence of normalized wing emission to the excited state molecular potentials. Both potentials are determined as a function of $R3$ from the integrated normalized emission in the infinite temperature limit. The upper state potentials are found to be attractive with a well depth of the order of $1000cm-1$. The excimer formation rate is observed from the pressure dependence of the wing fluorescence. For equilibrium conditions at 600 Torr, the excimers constitute $\sim$1% of the total excited sodium. Comparisons with Cs-rare gas and Rb-rare gas molecular potentials are made, and the possibility of lasing in the sodium system la discussed.