Electronically excited states of molecular hydrogen exposed to strong directcurrent, alternative current, or low-frequency laser fields

Abstract

Ionization rates and Stark shifts of electronically excited states of molecularhydrogen oriented parallel to an external electric or low-frequency electromagneticfield have been calculated within the fixed-nuclei approximation using athree-dimensional, fully correlated ab initio method. The investigation includesdoubly excited autoionizing states. It is found that field-induced (avoided)crossings between different electronic states lead to a breakdown of simple modelsfor predicting ionization rates.