Energy dependence of mass distributions in fragmentation

We study fragmentation numerically using a simple model in which an object is taken to be a set of particles that interact painwisely via a Lennard-Jones potential while the effect of the fragmentation-induced forces is represented by some initial velocities assigned to the particles. The motion of the particles, which is given by Newton's laws, is followed by molecular dynamics calculations. As time evolves, the particles form clusters which are identified as fragments. The steady-state cumulative distribution of the fragment masses is studied and found to have an effective power-law region. The power-law exponent increases with the energy given to the particles by the fragmentation-induced forces. This result is confirmed by experiments. (C) 1999 Elsevier Science B.V. All rights reserved.