Erlangen 2018 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 20: Plasma Wall Interaction II - Poster

P 20.7: Poster

Mittwoch, 7. März 2018, 16:15–18:15, Zelt West

Microscopic modeling of Ar atom scattering from a Pt(111) surface: a combined molecular dynamics and rate equation approach — •A. Filinov^1,2,3, D. Loffhagen², and M. Bonitz¹ — ¹ITAP, CAU Kiel, Leibnizstr. 15, 24098 Kiel — ²INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald — ³Joint Institute for High Temperatures, Izhorskaya Str. 13, 125412 Moscow

A combination of molecular dynamics (MD) simulation with a rate equation model is presented and applied to the trapping and scattering of rare gas atoms from metal surfaces. The temporal evolution of the atom fractions being either adsorbed or scattered into the continuum is investigated. We consider trapped, quasi-trapped and scattering states for this description, which are distinguished by an energetic criterion. The rate equations contain the transition probabilities between the states that can be uniquely determined from an analysis of the particle trajectories generated by MD. Once the system reaches quasi-equilibrium, the rates converge to stationary values, and the subsequent thermal adsorption/desorption dynamics is completely described by the rate equations without the need to perform time-consuming MD simulations. As a proof of our model, we present studies for Ar atoms interacting with a Pt(111) surface and obtain good agreement with the experiment. The dependence of the rates, kinetic energy and the energy-loss distribution functions on the incidence conditions and the lattice temperature is analyzed. Our model is important for the plasma-surface modeling as it allows to extend accurate simulations to longer time scales.