Fluorescence lifetimes of the O1Σg+, P1Σg+, R1Πg, and S1Δg states of H2

The rovibronic structures of gerade excited states of molecular hydrogen have been investigated between 117000 cm(-1) and the second dissociation limit with extreme ultraviolet visible double resonant excitation technique. Several levels have been unambiguously assigned to the nu = 0 state of the 4s and 4d Rydberg members 4s sigma O(1)Sigma(g)(+), 4d sigma P(1)Sigma(g)(+), 4d sigma R(1)Pi(g), and 4d delta S(1)Delta(g). The fluorescence lifetimes have been measured under collision free conditions for the first time, revealing that the lifetimes for the O(1)Sigma(g)(+)(nu = 0) state, 172.8 and 193.7 ns for J = 0 and 1, respectively, are much longer than those for the 4d Rydberg states. The rotational dependence of the lifetimes for the EF + GK + H(1)Sigma(g+), I(1)Pi(g), and J(1) Delta(g) states is discussed in terms of the nonadiabatic coupling among the upper gerade manifolds. (c) 2005 Elsevier Inc. All rights reserved.