Dynamical instability of one-dimensional Morse system

Dynamical instability in an one-dimensional many-body system with Morse-type interaction potential is studied by computer simulation. The dynamical instability of the Morse system is caused by two kinds of instability. One is the parametric instability caused by the stochastic fluctuation of positive curvature of a Riemannian manifold and the other is the local instability approximated by the local negative eigenvalues of the Hessian matrix for the potential function. We investigate the energy dependence of the maximal Lyapunov exponent in order to emphasize the characteristic dynamical instability of the Morse system and compare the characteristics with results have been reported in Fermi-Pasta-Ulam system and Lennard-Jones system. We also investigate the energy dependence of the particle diffusion in the Morse system.