Experimental and theoretical studies of the quenching of Li (3p , 4p) by N2

Quenching mechanisms of the Li͑(3p) and Li͑(4p) states in collision with the nitrogen molecule are studied by laser-induced fluorescence spectroscopy and by a quantum chemical calculation. The Li͑(3p) state is observed to be efficiently quenched to the Li͑(3s) state detected as intense 3s → 2p emission. The Li͑(4p) state is efficiently quenched to the Li͑(4s) and Li͑(3d) states detected as 4s-2p and 3d-2p emissions, respectively. The potential-energy surfaces for the Li͑(2s-4p)N2 states show a large number of conical intersections and avoided crossings resulting from the couplings between the ionic (Li^+ N2^−) and covalent configurations. There are a large number of stable excited states, and we give here the spectroscopic constants for the lowest two stable isomers correlating to Li͑(2p)+N2.