Photo-dissociation dynamics of a diatomic molecule: modelling of thermal and environmental effects

The quantum dynamics of photodissociation of a diatomic molecule interactin g with ultrashort infrared laser pulses and modelled by an appropriate Mors e oscillator with either a fixed or fluctuating well-depth is explored at n on-zero temperatures by assuming an initial state vector consistent with th e distribution of vibrational population at a given temperature. The time-d ependent Schrodinger equation is solved by the time-dependent Fourier grid Hamiltonian method. The computed dissociation rate constant k(T) at a given intensity and frequency, of the driving field passes through a maximum at an intermediate temperature. if the well-depth of the Morse oscillator fluc tuates randomly, mimicking medium-induced perturbations, k(T) shows a stron g suppression at specific values of the fluctuation frequency and strength. (C) 1999 Elsevier Science B.V. All rights reserved.