Bound state population and dissociation dynamics of a Morse oscillator with oscillating well-depth and driven by intense radiation: perturbative and numerical studies

Abstract

Bound state population dynamics in a diatom modelled by an appropriate Morse oscillator with a time-dependent well-depth is investigated perturbatively both in the absence and presence of high intensity radiation. For sinusoidally oscillating well-depth, the population of the mth bound vibrational level,P_mm (t), is predicted to be a parabolic function of the amplitude of the oscillation of the well-depth (ΔD₀) at a fixed laser intensity. For a fixed value of Δ D₀,P_mm (t) is also predicted to be quadratic function of the field intensity (ε₀). Accurate numerical calculations using a time-dependent Fourier grid Hamiltonian (TDFGH) method proposed earlier corroborate the predictions of perturbation theory. As to the dissociation dynamics, the numerical results indicate that the intensity threshold is slightly lowered if the well-depth oscillates. Possibility of the existence of pulse-shape effect on the dissociation dynamics has also been investigated.