Energy disposal distributions and cluster lifetimes of Ar-benzene clusters (ABC) were studied by quasiclassical trajectory calculations. Four intermolecular potentials, Lennard-Jones, ab initio, and two Buckingham-type potentials, were used in the calculations. The Ar atom was placed in one of the five minima of the potential surface at 0 K. The benzene monomer in ABC at 0 K was excited to various internal energies, and internal energy loss of the monomer following dissociation was calculated. The average energy removed, , depends on the well depth of the potential and on the initial structure of the cluster. The highest value was obtained when the cluster was formed at the deepest well, in which the Ar atom is above the center of the ring. Regardless of the initial structure, it was found that the atom migrated from well to well including the deepest, and dissociation occurred from a structure different from the initial one. No correlation was found between the energy removed and the cluster lifetime, i.e., the dissociation process is history independent. Rotations and out-of-plane vibrations play a major role in the dissociation process. Except for the lowest values of Delta E, the energy disposal probability density function, P(E',E), is exponential in Delta E. The cluster lifetime distributions depend on the potential, and can be fit by multiexponential functions. Within a given potential, the shallower the well the narrower the temporal distribution, and the higher the internal energy of ABC the shorter the lifetime. Application of Rice-Ramsperger-Kassel-Marcus (RRKM) theory to cluster modes, which contain an amount of energy Delta E, yields lifetimes with values similar to those obtained directly from trajectory calculations. A comparison is made between P(E-',E), , and lifetimes obtained in cluster-dissociation and gas-phase collision calculations for identical inter- and intramolecular potentials. Energy transfer quantities and lifetimes are larger in clusters, while the mechanism of energy transfer and the contribution to it of rotations and out-of-plane vibrations are similar in both systems.