Photoionization cross sections of rovibrational levels of the B 1Σ+u state of H2

Abstract

We report theoretical cross sections for direct photoionization of specific rovibrationallevels of the B 1 ~u+ electronic state of H 2 • The calculated cross sections differ considerably from values recently determined by resonant enhanced multiphoton ionization (REMPI) studies. In an attempt to understand the disagreement, we analyze in detail the REMPI dynamics and find that the multi photon ionization probability is extremely sensitive to the spatial and temporal profiles of the laser pulses. Accurate characterization oflaser profiles and their jitter is therefore necessary for a comparison between theory and experiment.

(2+1) resonant enhanced multiphoton ionization of H2 via the E,F 1Σ+g state

“…We have, in the present work, neglected the effects of saturation and the possible presence of autoionization features in the continuum. In a previous pa-per 14 we have shown the sensitivity of the calculated results to the inclusion of saturation effects. The effects of the Rydberg-valence mixing on the photoelectron angular distributions and vibrational branching ratios are expected to be even more dramatic if the outer-well vibrational states vF = 0, 1,2,3, i.e., vE,F = v; = 1,2,4,5 were accessed.…”