AUTOIONIZATION RATES AND ENERGY-LEVELS OF TRIPLET NF, V=1 RYDBERG STATES OF H2

We have measured the linewidths of 35 different triplet Rydberg states of the H2 molecule with quantum numbers n=1022, L=3, v=1, and R=04. An 18-eV electron beam excites a collimated H2 beam to the metastable c(2p)3 u state. Stepwise excitation using two counterpropagating cw single-mode dye laser beams excites the metastable molecule first to an intermediate state [(3d)3 or (3d)3] and then to a triplet nf Rydberg state. The linewidths for the nf Rydberg states give the autoionization rates, which agree satisfactorily with the polarizabilityquadrupole-moment long-range interaction model. We also have measured the transition frequencies between these states to an accuracy of 0.002 cm-1. We use these measurements to derive the ionization potential of the metastable triplet state to an accuracy of 0.020 cm-1 and the energy difference between the metastable and ground states of H2 to an accuracy of 0.025 cm-1. © 1990 The American Physical Society.