The influence of a femtosecond laser pulse on an adsorbate molecule-metal surface system is investigated by considering a time-dependent coupling between the ground-and excited-state potential energy curves using the time-dependent quantum mechanical wave packet approach. It is shown that the probability of desorption is strongly dependent on the duration of the coupling and the image-charge attraction and that it increases with increase in vibrational excitation of the metal-adsorbate bond.