SPECTROSCOPIC STUDY OF THE 2ND PI-3(G) STATE OF H2 - A BOUND TRIPLET-STATE PERTURBED BY A DOUBLY EXCITED-STATE

A double-resonance technique is employed to measure the positions of energy levels of the second 3Πg state of H2. Vibrational levels of this state with v > 3 lie above the ionization threshold of H2+, and are observed both to autoionize and dissociate. This state, 23Πg, arises from the homogeneous interaction between the singly excited 1sσg 3dπg and 1sσg 4dπg diabatic Rydberg states with the core-excited 2pσu 2pπu state. The energy-level spacings are in good agreement with a simple model calculation for the interacting potentials. We also include a listing of autoionizing levels lying in the same energy range. © 1990 American Institute of Physics.