Simulation of keV clusters incident on gold targets

Abstract

Using molecular dynamics (MD) simulations, Shapiro and Tombrello predicted that keV clusters containing a mixture of light and heavy atoms can eject a substantial fraction of their lighter atoms away from a target surface, a phenomenon they designate "splash". Recently, experiments by Diehnelt et al. and Brunelle et al. have shown evidence of fluorine and deuterium splash in systems of (NaF)nNa+ and deuterated valine, respectively, incident on gold targets. Although direct yields cannot be compared due to unknown ionization efficiencies in the experiments, this paper describes further simulations which provide insight into the experimental systems. For the (NaF)_(n)Na^+ clusters, our results agree reasonably well with the observed trend in fluorine splash as a function of cluster energy but predict a different dependence on cluster size. For the valine system, we find the same dependence of the yield on cluster size as the experiment.

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