We analyze the results of recent pump-probe experiments on the site-switching dynamics of Ar within cationic phenol-Ar(2) clusters. A reaction-path model is employed for the wave packet dynamics. It is shown that the mechanism of energy dissipation is to be included to understand the features of the transient signals. Therefore, a simple recipe to include energy relaxation to the quantum dynamics is introduced. It is then possible to reproduce the measured pump-probe signals by adjustment of only two parameters.