Above-threshold dissociation ofH2+in intense laser fields

Abstract

We present nonperturbative, time-independent calculations of the photodissociation rate of ${\mathrm{H}}_2^{+}$ in intense laser fields. The energy distribution of the protons consists in a sequence of peaks evenly spaced by half the photon energy, all of equal width but of varying heights. They result from multiphoton absorption above the dissociation threshold, with equal sharing of the excess photon energy between H and ${\mathrm{H}}^{+}$. Surprisingly, the distribution of higher-energy peaks decreases with increasing intensity, due to stimulated free-free emission of the dissociating fragments. We also predict a sharp angular distribution of the protons along the electric field vector of a linearly polarized laser.