Photodissociation of Ar2+ in strong laser fields Original Research Article

We present extensive calculations for the dissociation of Ar2+ caused by the interaction with strong (Ipeak≲1014W/cm2) and short (T < 5 ps) laser pulses; the calculations are stimulated by the recent experimental study of Wunderlich et al. [Chem. Phys. Lett. 256 (1996) 43]. The time-dependent Schrödinger equation is solved exactly within a two-state model including the binding ground state, A2Σu+, and the repulsive excited state, D 2Σg+. In order to get a most complete picture of the dissociation process the intensity and the frequency of the laser pulse as well as the initial vibrational state of Ar2+ are varied over large ranges. It is observed that the reflection principle, known from spectroscopy with long and weak light sources, governs — at least qualitatively — the dissociation dynamics up to relatively high intensities. Special strong-field effects such as stabilization occur, if at all, at very high intensities; in general, however, they are rather insignificant for the intensity range probed in the experiment.