We investigate the mechanism of enhanced ionization in two-electron molecules by solving exactly the time-dependent Schrödinger equation for a one-dimensional [Formula Presented] in an ultrashort, intense [Formula Presented] laser pulse [Formula Presented] Enhanced ionization in two-electron systems differs from that in one-electron systems in that the excited ionic state [Formula Presented] regarded as the dominant doorway state to ionization crosses the covalent ground state HH in field-following time-dependent adiabatic energy. An analytic expression for the crossing condition obtained in terms of the lowest three states agrees with the numerical results. The gap at the avoided crossing decreases the initial covalent component and promotes electron transfer to [Formula Presented] As the internuclear distance R decreases, the population of the [Formula Presented] created increases, whereas the ionization rate from a [Formula Presented] decreases owing to the stronger attraction by the distant nucleus. As a result, the rate has a peak at [Formula Presented] where most adiabatic states avoid each other with considerable gaps.
|ジャーナル||Physical Review A - Atomic, Molecular, and Optical Physics|
|出版ステータス||Published - 2000 1 1|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics