title: Fission of multiply charged alkali clusters in helium droplets - approaching the Rayleigh limit.
abstract: Electron ionization of helium droplets doped with sodium, potassium or cesium results in doubly and, for cesium, triply charged cluster ions. The smallest observable doubly charged clusters are Na9(2+), K11(2+), and Cs9(2+); they are a factor two to three smaller than reported previously. The size of sodium and potassium dications approaches the Rayleigh limit nRay for which the fission barrier is calculated to vanish, i.e. their fissilities are close to 1. Cesium dications are even smaller than nRay, implying that their fissilities have been significantly overestimated. Triply charged cesium clusters as small as Cs19(3+) are observed; they are a factor 2.6 smaller than previously reported. Mechanisms that may be responsible for enhanced formation of clusters with high fissilities are discussed.
authors.affiliation: Institut für Ionenphysik und Angewandte Physik, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria. paul.scheier@uibk.ac.at Michael.Renzler@uibk.ac.at Martina.Harnisch@uibk.ac.at Matthias.Daxner@uibk.ac.at Lorenz.Kranabetter@student.uibk.ac.at Martin.Kuhn@uibk.ac.at.
authors.forename: Michael
authors.initials: M
authors.lastname: Renzler
authors.forename: Martina
authors.initials: M
authors.lastname: Harnisch
authors.forename: Matthias
authors.initials: M
authors.lastname: Daxner
authors.forename: Lorenz
authors.initials: L
authors.lastname: Kranabetter
authors.forename: Martin
authors.initials: M
authors.lastname: Kuhn
authors.forename: Paul
authors.initials: P
authors.lastname: Scheier
authors.forename: Olof
authors.initials: O
authors.lastname: Echt