FOURIER-TRANSFORM SPECTROSCOPY OF THE 1(3)DELTA-G-B(3)PI-U TRANSITION IN LI-6(2)

The 13Δg-b3Πu transition of 6Li2 has been observed in collisionally induced fluorescence following (a) excitation of the C1Πu state by the ultraviolet lines of argon and krypton ion lasers and (b) single frequency double resonance excitation of the F1Σg+ state using a ring dye laser operating with DCM dye. Spectra were obtained at high resolution using Fourier transform spectrometers. Many lines are broadened and shifted because of predissociation of b3Πu by a3Σu+; the widths and shifts have been measured as a function of rotation and vibration. Several perturbations have been observed in the 13Δg state and are shown to be caused by interaction with the 23Πg state. The data are reduced to molecular constants (Dunham coefficients), perturbations are analyzed, and the collisional mechanism responsible for excitation of the 13Δg state is discussed. © 1992.