Driving-laser wavelength dependence of high-order harmonic generation in H2+ molecules

The electron-nuclear dynamics of one-dimensional H-2(+) molecular high harmonic generation is investigated by numerical integration of the non-Born-Oppenheimer time-dependent Schrodinger equation. It is found that the nuclear motion and electron ionization are more significant for the longer wavelength and the stronger intensity of the driving laser pulse. When the ground-state H-2(+) molecule is driven by a short laser pulse (ten optical cycles in the calculations), a strong signature of nuclear motion is seen in the wavelength scaling (800-2000 nm) of harmonic yield, following a lambda(-(7-8)) scaling law at a constant laser intensity. It is attributed to the fast ground-state depletion induced by the strong nuclear motion, when using the long wavelength. Consequently, the wavelength scaling gives an insight into the nuclear dynamics.