The rotationally resolved 1(3)Sigma(+)(g)<-1(3)Sigma(+)(u) transition in Na-2 studied by resonant two-photon ionization in a molecular beam

The 1(3) Sigma(g)(+) <-- 1(3) Sigma(u)(+) band system of the sodium dimer has been studied with rotational resolution in a supersonic molecular beam. The laser excited triplet-triplet transitions have been monitored by observation of the resonantly enhanced ionization of Na-2 (1 (3) Sigma(g)(+)) induced by the light of a second laser. The molecular constants for the observed vibrational levels of both tripler states are derived from the experiment and compared with the results of ab initio calculations.