FRAGMENTATION ANALYSIS OF SIZE SELECTED SODIUM CLUSTERS

摘要

The fragmentation processes of small sodium clusters induced by photoionization are investigated for a size selected neutral cluster beam. We use the collision induced momentum transfer in a crossed beam experiment to achieve the separation of the masses. Photoions produced with photon energies up to 4.66 eV are mass analyzed in a time-of-flight mass spectrometer. A considerable amount of fragmentation is observed leading exclusively to population of ionic channels with an even number of electrons. The measured fragmentation probabilities for cluster sizes up to n=8 are compared to a statistical unimolecular decay model. This gives a satisfactory agreement also for the photon energy dependence of the fragmentation probabilities if one assumes a significant contribution from cluster isomers. (C) 1997 American Institute of Physics. [References: 27]