Influence of nuclear vibration on harmonic generation in molecules

The effect of vibrational motion on harmonic generation inmolecules is studied within the strong-field approximation. Simple expressions are given for the cut-off energy and for the ratio of spectral intensities from two isotopes. The latter is based on electronic trajectories from the simple-man's model. The influence of vibration is given by a correlation function that is sensitive to the overlap between the initial vibrational wave packet and the wave packet after the evolution in the Born-Oppenheimer potential of the ionized molecule.