FIELD-IONIZATION RATES OF THE HYDROGEN MOLECULAR ION

We calculate the quasienergies and wavefunctions of the hydrogen molec ular ion perturbed by a strong external electric field. Results are ob tained for static-held ionization rates of the lowest dressed states. The nonlinear Stark shifts are also calculated for weak and strong fie lds for a range of internuclear separations. Charge and current densit ies are obtained and used to explain the ionization resonance structur e. The ionization currents are found to be very sensitive to field str ength and internuclear distance. There is evidence of critical distanc es that indicate the validity of Coulomb explosion models and electron localization. However, for this system, the results do not agree well with simple over-barrier models of electron release. Multiphoton ioni zation rates of low-frequency intense laser fields are estimated by cy cle averaging.