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

The quantum dynamics of photodissociation of a diatomic molecule interacting with ultrashort infrared laser pulses and modelled by an appropriate Morse oscillator with either a fixed or fluctuating well-depth is explored at non-zero temperatures by assuming an initial state vector consistent with the distribution of vibrational population at a given temperature. The time-dependent Schrِdinger 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 fluctuates randomly, mimicking medium-induced perturbations, k(T) shows a strong suppression at specific values of the fluctuation frequency and strength.