Low energy cluster impact simulated by molecular dynamics; angular distribution of sputtering yield and impact under various angles

Knut Barghorn
Eberhard R. Hilf   Phone: +49-441-798-2543   Fax: +49-441-798-3201


Date: 1994

Article: published in Nuclear Instruments and Methods in Physics Research NIM B 88 (1994) p. 196

The collision process of low energetic gold atoms and solid targets has been
simulated using our molecular dynamics simulation code CLIMPACT II. The used
algorithm is a third-order predictor Verlet algorithm [ L. Verlet, Phys. Rev.
159 ( 1967 ) 98; W. F. van Gusteren and H. J. C. Berendsen, in: Molecular
Liquids - Dynamics and Interfaces, A. J. Barnes et al., eds ( Reidel, 1984 ) p.
475. ] . The iteration time step is continuously optimized by the program.
About 50%  of the total computer time is spent to integrate the motions during
the first 100 fs of simulation time  [ B. Nitzschmann, Diploma thesis,
Univ. of Oldenburg, Germany, ( 1992 ) ] . When the crater formation ends and
the motions in the target are slower, the step increases up to 20 times the
start step size. Using this algorithm we are able to simulate a target of up to
105  particles. We use new nonreflecting boundary conditions. Only mechanical
interactions are considered. The projectile can be chosen as a cluster with
variable impact angle. Specifically the output yield under different impact
angles and the distribution of the desorbed particles are presented and
discussed. The temporal development of the desorption shows three distinct
processes: an early explosive process, a surface ablation by an apparent
surface shock wave, a final thermal evaporation.

DC-Metatags done by WUFI 1.1
Metadata by Thomas Severiens on 25 November 1998
Supporting work done by Sandra Valeska Bergmann.