The 2(3)Pi(g)-b(3)Pi(u) and 1(3)Delta(g)-b(3)Pi(u) transitions in Li-7(2): Analysis of the b(3)Pi(u) State for v=0-27

Two double resonance techniques, perturbation facilitated optical-optical double resonance (PFOODR) and collision induced fluorescence (CIF), have been used to excite the 2(3) Pi(g), (PFOODR only) and 1(3) Delta(g) states of Li-7(2). Fluorescence from each of these states to the b(3) Pi(u) state has been studied at high resolution using Fourier transform spectroscopy. Transitions were observed and analyzed up to upsilon = 27 in the b(3) Pi(u) state, and the PFOODR and CIF data have been combined to give an improved set of Dunham coefficients from which an RKR potential has been calculated. Predissociation by the a(3) Sigma(u)(+) state, which broadens and shifts the b(3) Pi(u)(+), levels, has been studied in detail. The level shifts to upsilon = 27 have been calculated and the observed values are shown to follow the theoretically predicted pattern. The isotope effect on the predissociation has also been examined. The l(3) Delta(g) state has been analyzed for 0 less than or equal to upsilon less than or equal to 25 and molecular constants and an RKR potential have been calculated. (C) 1997 Academic Press.