Lifetimes, population and deactivation mechanisms of the C 1Πu, 2 3Πg and 2 1Σ+u states of Na2

The UV and visible fluorescence of Na2 molecules in a heat-pipe, excited by the frequency doubled radiation of a tunable mode-locked cavity-dumped cw dye laser was observed through a monochromator, using time-resolved single-photon counting. The effective lifetimes of the directly excited C 1Πu state and the collisionally populated 2 3Πg and 2 1Σ+u states have been measured as a function of sodium-vapor pressure and argon pressure which yields the radiative lifetimes, the population mechanisms and the collisional quenching cross sections of the three states. (orig.)