Energy-dependent cross sections for quenching of Li(2p 2P) by several gases

The lifetime of Li(2p 2P), in the presence of H2, D2, N2, CO, I2, CO2, C2H4, C2H6, and C2F6 as quenching gases, has been directly determined by the single-photon time-correlation method. Li(2P) atoms were produced with varying amounts of translational energy by photodissociation of LiI with light of wavelenghts from 2000 to 2300 Å. Large quenching cross sections, comparable to those observed for heavier alkali metal atoms, were found. The results are discussed in terms of an orbiting trajectory model and a ’’harpooning’’ model.