Abstract:
In the present paper the nonlinear characteristics of one-body dissipative of an excited finite nucleus has been studied by simulating the evolution of the nucleus
208Pb within the Quantum Molecular Dynamics (QMD) model . First, the phase diagram of the nucleus and the spinodal region were determined by computing the single particle energy and chemical potential. Then the position and momentum of each nucleons in the
208Pb were sampled according to uniform and fermi distribution respectively. After such preparation, taking these distributions as initial sates of QMD model, we simulated the evolution of the system in the action of the mean field with no collision term. The variation of the density and the fluctuation of the nucleons distribution have been analyzed. Our main attention paid on the comparison of the behavior of such quantities for the system started from
208Pb with different initial states. The sensitivity of the mean field dynamics on the initial space distribution of nucleons are demonstrated by calculating the Lyapunov exponents defined respectively in events space and phase space. The nonlinear dynamical mechanism of the one-body dissipation, and thus the multifragmentation of heavy-ion collisions at intermediate energy have been confirmed further. The conclusion is helpful for us both to understand the dynamical mechanism of the heavy-ion reactions and to extend our knowledge about the nonlinear dynamics.