Interactions of fast C-20 clusters with solids: Coulomb explosions, charge states and energy losses

摘要

The dielectric response formalism is used to evaluate the dynamically screened interaction potential among the ions in a fast C-20 cluster passing through a solid target. This potential is further used to calculate the individual ion charge states in the cluster by means of a statistical-variational theory which takes into account the effects of the vicinity of the neighbouring ions. Coulomb explosion and the energy losses of the cluster are simulated by solving equations of motion for individual ions while taking into account, in a self-consistent manner, the variation of ion charges in the course of explosion. Moreover, a Monte Carlo method is used to simulate the effects of multiple scattering of cluster constituent ions on target atoms. It is found that, owing to the wake-like asymmetry of the inter-ionic potential, both the distribution of ion charges in the cluster and the Coulomb explosion patterns exhibit strong spatial asymmetries in the direction of motion. It is also shown that the cluster energy losses exhibit characteristic interferences due to the vicinity effects, which diminish after long dwell times. [References: 24]