Electron bombardment fragmentation of Ar van der Waals clusters by scattering analysis

Abstract

Arn clusters generated in a supersonic nozzle beam are investigated by exploiting their different kinematical behavior in a scattering experiment. In a crossed molecular beam experiment the Arn clusters are scattered from He atoms at E=69.7 meV. By measuring the angular and velocity distributions of the scattered clusters, the different species can be separated from each other. In this way fragmentation probabilities of small Arn clusters up to n=6 by electron impact ionization are measured. The influence of collisional dissociation of the dimer is accounted for by classical trajectory calculations. The dimer fragmentation is found to be f21=0.40±0.05, while the trimer totally fragments to dimers ( f32=0.7±0.3) and monomers ( f31=0.3). All clusters with n from 4 to 6 appear with a probability of 0.95 on the dimer ion mass.

Binding energies and scattering observables in the 4He3 atomic system

“…From the experimental studies we mention those of Refs. [32][33][34][35][36][37] where molecular clusters, consisting of a small number of noble gas atoms, were investigated.…”

Ultralow energy scattering of a He atom off a He dimer

“…From the experimental works we recall those of Refs. [12][13][14][15] where molecular clusters consisting of a small number of noble gas atoms were investigated.Despite the efforts made to solve the He-trimer problem various questions such as the existence of Efimov states and the study of scattering processes at ultra-low energies still have not been satisfactorily addressed. In particular for scattering processes there are no works which we are aware of apart from a recent study concerning recombination rates [16].…”

“…From the experimental works we recall those of Refs. [12][13][14][15] where molecular clusters consisting of a small number of noble gas atoms were investigated.…”

Thermodynamic properties and homogeneous nucleation rates for surface-melted physical clusters

“…8 Neutralization of size-selected ionic clusters produces a narrow size distribution of clusters, but the vibrational energy of the neutralized clusters exceeds that of thermalized clusters at the temperature of the incoming cluster beam. 9 Deflection of a neutral cluster beam with an atomic beam has been used to separate a cluster beam with atomic resolution for small clusters ͑less than 10 rare gas atoms 10 or up to 13 molecules 11 ͒. Many applications require knowledge of the properties of larger clusters.…”