Ionization of hydrogen molecular ions in an intense laser field via a resonant state Original Research Article

We present a time-dependent Schrödinger equation method in the prolate spheroidal coordinates to study the double ionization of hydrogen molecules in an intense laser field. The time propagation of the electronic wave function is performed by a second order split-operator method in the energy representation. With an adiabatic approximation, we obtain the kinetic energy release (KER) spectra by folding the vibrational wave packet of nuclei with the calculated ionization rates. Our results are in reasonable agreement with the experimental measurement. Furthermore, by including or excluding an individual state in the calculation, we identify that the observed KER peak comes from the ionization of the hydrogen molecular ions via the three-photon resonance of the image state.