Role of Electron Localization in Intense-Field Molecular Ionization

The rate of nonlinear ionization is strongly enhanced as a molecule is stretched beyond its equilibrium internuclear separation, reaching a peak rate that is many orders of magnitude greater than that at either small or large distances. The enhancement results from nonadiabatic electron localization near the nuclei and its presence is insensitive to the laser frequency and intensity. Most intense-field dissociative ionization experiments are influenced by this effect.