Osnabrück 2002 – wissenschaftliches Programm

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A: Atomphysik

A 12: Cluster IV: Molekulare Cluster, Theorie (gemeinsam mit FV Molekülphysik)

A 12.6: Vortrag

Mittwoch, 6. März 2002, 17:45–18:00, HS 01/E01

Molecular dynamics simulations of water clusters scattering from graphite — •Anna Tomsic¹, Nikola Markovic², and Jan B.C. Pettersson³ — ¹Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 München — ²Department of Physical Chemistry, Chalmers University of Technology, 412 96 Göteborg, Sweden — ³Department of Chemistry, Physical Chemistry, Göteborg University, 412 96 Göteborg, Sweden

(H₂O)_n, n <= 25159, colliding with a graphite surface at normal incidence have been carried out. The incident velocity ranged from 50 to 2000 ms⁻¹ and the surface temperature was between 300 K and 1400 K. Upon impact, the cluster is deformed elastically (reversibly) and plastically (irreversibly), and if the elastically stored energy is larger than the adhesion energy between the cluster and the surface, the cluster scatters directly from the surface. The partitioning between elastic and plastic deformation is governed by the initial conditions (cluster temperature, incident velocity, incident cluster size and surface temperature). At low incident velocities the scattering probability is controlled by adhesion and at high incident velocities by plastic deformation, and the direct scattering is thus confined to a narrow range of incident velocities. The results are in qualitative agreement with recent experimental studies of water clusters scattering from graphite.