Two-photon dissociation of HD+ with one intermediate resonance in the presence of two different laser fields

Abstract

The time-dependent dissociation probabilities, line shapes of dissociation rate, and photofragment kinetic-energy distribution have been investigated for resonant two-photon dissociation of HD+ from the 1sσg(v=0, J=0) state in the presence of two radiation fields of different frequencies ω1 and ω2. Simultaneous dissociation in two different electronic states at two different final energies occur through the absorption of either ω1+ω2 or 2ω2 photons. Only one of the two fields causes a near-resonant coupling either with (v=6, J=1) through absorption of a photon of frequency ω1 or with the (v=14, J=1) state through absorption of a photon of frequency ω2. Dissociation probabilities have been calculated as functions of the resonant and off-resonant field amplitudes and times. The dissociation probability at fixed times show interesting variation with the field amplitudes. Conditions for time-dependent interference oscillations in dissociation probabilities are discussed and these oscillations demonstrated. Intensity-dependent line shapes for dissociation rate are obtained for various other combinations of fields. Long-time kinetic-energy distribution of photofragments is similar to the energy spectrum of photoelectrons obtained from atomic autoionization. The photofragment spectra for two energies in two final electronic continuum states are compared for different values of the field amplitudes and detunings.