FLUORESCENCE LIFETIMES OF EF1-SIGMA-G+, GK1-SIGMA-G+, H1-SIGMA-G+, I1-PI-G, AND J1-DELTA-G STATES OF H-2 STUDIED BY EXTREME ULTRAVIOLET VISIBLE DOUBLE-RESONANCE EXCITATION

Extreme ultraviolet-visible double resonance excitation has been employed to populate the EF 1-SIGMA(g)+, GK 1-SIGMA(g)+, H 1-SIGMA(g)+, I 1-PI(g), and J 1-DELTA(g) states of hydrogen molecules in the range between 111 500 and 114 000 cm-1. Tunable coherent extreme ultraviolet radiation prepared H-2 in the B 1-SIGMA(u)+ (upsilon = 5, J) state. The visible laser radiation subsequently brought H-2 to higher gerade states. Term values were determined for the J' = 0-4 levels, which confirmed the systematic error of 8.01 +/- 0.03 cm-1 in the previous analysis by Dieke. The single rovibronic fluorescence lifetimes were measured under a collision-free condition. The fluorescence lifetimes of the I 1-PI(g)(upsilon' = 0) and J 1-DELTA(g)(upsilon' = 0) states, approximately 20 and 25 ns, respectively, were found to depend little on the rotational levels. The EF 1-SIGMA(g)+ GK 1-SIGMA(g)+ and H 1-SIGMA(g)+ states, on the other hand, exhibited significant rotational dependence. The nonadiabatic coupling among the upper gerade manifolds explained the observed rotational dependence successfully.