Dynamical interference of H and H2+ in one-photon ionization

Abstract

The non-Hermitian Floquet theory is applied to systematically calculate both the ac-Stark shift $\ensuremath{\delta}$ and the decay rate $\ensuremath{\gamma}$ for hydrogen atoms and hydrogen molecular ions, when placed in a high-frequency laser field with an intensity ranging from the perturbation to the stabilization region. This allows us to trace the appearance of dynamical interference in ionization. We find that both the stabilization and the dynamical interference are easier to achieve at a frequency close to the ionization threshold. For the molecular case, the effects of nuclear motion are discussed based on the Born-Oppenheimer approximation. Although the dynamical interference condition $\ensuremath{\delta}g\sqrt{\ensuremath{\pi}}\ensuremath{\gamma}$ seems to be satisfied at a low frequency for a fixed-nuclei ${{\mathrm{H}}_{2}}^{+}$ in the perturbation region, the effects of the nuclear motion are shown to destroy the interference patterns in this region. Meanwhile, for the sake of confirmation, the photoelectron energy distributions are calculated by solving the time-dependent Schr\odinger equation for the parameters where the dynamical interference is predicted by the non-Hermitian Floquet theory.