FRAGMENTATION OF ATOMIC CLUSTERS - A THEORETICAL-STUDY

Collisionless fragmentation of nonrotating model n-atom metal clusters (n = 12, 13, and 14) is studied using isoergic molecular-dynamics sim ulations. Minimum-energy paths for fragmentation are mapped out as fun ctions of the distance between the centers of mass of the fragments. T hese paths provide information on the fragmentation energies for the d ifferent fragmentation channels. Fragmentation patterns (distributions of the fragmentation channel probabilities) and global and channel-sp ecific fragmentation rate constants are computed and analyzed as funct ions of the internal energy and of the size of the clusters. The trend s derived from the dynamics are compared with those obtained using the RRK and TST statistical approaches. The dynamics of the fragmentation process is analyzed in terms of characteristic quantities such as the distance between the centers of mass of the fragments, their relative translational energy, and their interaction energy, all considered as functions of time.