MOLECULAR-DYNAMICS STUDY OF NEUTRAL AND MULTIPLY-CHARGED SODIUM CLUSTERS

The fission mechanism of multiply charged sodium clusters was investig ated with molecular dynamics and a new potential featuring a local den sity approximation second-moment approach. We show that the critical s ize at which 2+, 3+ and 4+ charged clusters undergo fission due to Cou lomb forces depends strongly on the cluster temperature. The smallest critical sizes occur for cold clusters. Master curves predicting upper bounds to the cluster temperature at the fissioning critical size are provided. A scaling of the cluster ion critical size with a power law of the total charge is used to predict the energy barrier that sodium clusters need to surmount to undergo fission. (C) 1997 Elsevier Scien ce B.V.