ONE-BODY DISSIPATION AND CHAOTIC DYNAMICS IN A CLASSICAL SIMULATION OF A NUCLEAR GAS

In order to understand the origin of one-body dissipation in nuclei, w e analyze the behavior of a gas of classical particles moving in a two -dimensional cavity with nuclear dimensions. This ''nuclear'' billiard has multipole-deformed walls which undergo periodic shape oscillation s. We demonstrate that a single-particle Hamiltonian containing coupli ng terms between the particle motion and the collective coordinate ind uces a chaotic dynamics for any multipolarity, independently of the ge ometry of the billiard. If the coupling terms are switched off, the '' wall formula'' predictions are recovered. We discuss the dissipative b ehavior of the wall motion and its relation to the order-to-chaos tran sition in the dynamics of the microscopic degrees of freedom. [S0556-2 813(98)03911-9].