Time-dependent size distribution of xenon-cluster ions

Abstract

The evaporation of monomers following electron-impact ionization causes a significant enhancement of the intensity anomalies (‘‘magic numbers’’) in mass spectra of xenon clusters. The dissociation rates are measured on a microsecond time scale for clusters containing between 10 and 79 atoms. The highest dissociation probability, 99(1)%, is found for ${\mathrm{Xe}}_{57}$ ${\mathrm{}}^{+}$, which is two atoms larger than a closed-shell icosahedral cluster. Each anomaly in the dissociation rates corresponds to an intensity anomaly (‘‘magic number’’) in the mass spectrum. Recent Monte Carlo simulations for ${\mathrm{Xe}}_{\mathrm{n}}$ ${\mathrm{}}^{+}$, n≤30, are in full agreement with our experimental results.