Molecular dynamics studies of inelastic scattering and fragmentation in collisions of with rare-gas atoms

Abstract

Collisions of with neon and helium atoms were studied using molecular dynamics with empirical two- and three-body forces. Inelastic scattering including the capture of the rare-gas atom and fragmentation were analysed at collision energies in the centre-of-mass system between 1 and 200 eV with sufficient statistics for the microscopic calculation of differential cross sections on an absolute scale. The angular distributions are characterized by enlarged average deflections of the rare-gas atom due to the surface corrugation at low collision energies and shooting through the at high collision energies . The kinetic-energy spectra of the scattered rare-gas atoms indicate the extreme inelasticity of in collisions. Good agreement between calculated and measured kinetic-energy spectra from collisions was found. In particular, the position of the inelastic peak at the low-energy end of the spectrum was reproduced perfectly. Cross sections for the formation of compounds were calculated in order to provide a measure for the fine tuning of potential parameters. The calculated mass spectra of the primary fragments at 200 eV collision energy exhibit a bimodal distribution with a few fission-like events in collisions. Double differential cross sections for the kinetic energy of cluster fragments formed as a direct result of the impact demonstrate the non-thermal character of this direct fragmentation of at high collision energies.