First observation of a collisionally induced diffuse band of 7Li 2 around 452 nm

Abstract

We report on the first clear observation of a collisionally induced diffuse band of lithium dimer around 452.0 nm in direct single photon excitation using 337.1 nm (N 2) laser radiation from an excimer laser. The band, which is being tentatively assigned to the 2 1Σ + u → X 1Σ + g transition and could only be observed at buffer gas pressures of ⩾ 75 mbar, had been theoretically pre dicted. We also report on the other violet band of Li 2 around 458.0 nm, already assigned to the 2 3Π g → a 3Σ + u transition. Parametr ic dependences for the two bands are presented. Together with these continuum emissions, a number of strong atomic lithium lines are also observed. A possible correlation between the atomic and continuum emissions is presented which may help in a better understanding of the kinetics of the system.