Experimental and theoretical studies of the quenching of Li (3p,4p) by N 2

Quenching mechanisms of the Li (3p) and Li (4p) states in collision with the nitrogen molecule are studied by laser-induced fluorescence spectroscopy and by a quantum chemical calculation. The Li (3p) state is observed to be efficiently quenched to the Li (3s) state detected as intense 3s→2p emission. The Li (4p) state is efficiently quenched to the Li (4s) and Li (3d) states detected as 4s-2p and 3d-2p emissions, respectively. The potential-energy surfaces for the Li (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 Li (2p) + N2. © 2005 American Institute of Physics.