https://doi.org/10.1140/epjd/e2006-00118-y
Hyperthermal cluster-surface scattering
Comparison of fragmentation, energy redistribution, and sticking in atomic and molecular clusters
Fachbereich Physik, Universität Kaiserslautern, Erwin-Schrödinger-Straße, 67663 Kaiserslautern, Germany
Corresponding author: a urbassek@rhrk.uni-kl.de
Received:
31
January
2006
Revised:
27
March
2006
Published online:
7
June
2006
Using molecular-dynamics simulation, we study the processes occurring after impact of clusters on a rigid wall. Comparing the impact of model clusters consisting of 13 atoms, or of 13 diatomic molecules with varied bond strength, the systematics in the results of the collision process are investigated. Four regimes of impact-induced cluster fragmentation are identified: intact reflection, shattering into large fragments, complete fragmentation, and molecule dissociation. The effect of the number of degrees of freedom activated in the collision on the translational and internal energies of the reflected fragments is discussed in detail. As a rule, with increasing number of degrees of freedom which can be activated in the collision, the translational energy sinks. On the other hand, for weak intramolecular bonding, intramolecular vibrations are easily excited at small impact energies, reducing the resulting translational energy. The presence of even a very weak attractive well ϵw at the surface has a major influence on the sticking behavior of the clusters — and hence also on the absolute reflected energies — even at impact energies E0 ≫ ϵw.
PACS: 68.49.Fg – Cluster scattering from surfaces / 36.40.-c – Atomic and molecular clusters / 79.20.Ap – Theory of impact phenomena; numerical simulation
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006