The EF, GK, H1Σg+, I1Πg, and J1Δg states of HD:: Term values and fluorescence lifetimes

Vacuum ultraviolet-visible double resonance excitation has been employed to populate rovibronic levels of the EF, GK, H(1)Sigma(g)(+), I(1)Pi(g), and J(1)Deltag states of HD in the range between 113000 and 118600 cm(-1) above the ground-state X(1)Sigma(g)(+). Tunable coherent vacuum ultraviolet light, generated by a four-wave mixing process in Xe, prepares HD in the intermediate B(1)Sigma(u)(+) (upsilon = 6, 7, and 10) state. Subsequent absorption of visible laser radiation brings HD to the higher gerade states. Term values of 42 rovibronic levels are determined for the first time. The single rovibronic fluorescence lifetimes are measured under collision-free conditions. The observed lifetimes for the H(1)Sigma(g)(+) state are generally longer than the theoretical values, whereas those of the EF and GK(1)Sigma(g)(+) states are considerably shorter than the calculations. The rotational variation of the EF(1)Sigma(g)(+) state lifetimes can be well understood in terms of the nonadiabatic coupling among the upper gerade manifolds. The rotational dependence of the lifetimes for the GK(1)Sigma(g)(+) state exhibits a good correspondence to the coupling with the nearby B(1)Sigma(u)(+) rovibronic levels.