Berlin 2014 – wissenschaftliches Programm

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K: Fachverband Kurzzeitphysik

K 7: Poster

K 7.2: Poster

Mittwoch, 19. März 2014, 16:30–18:30, SPA Foyer

Molecular Dynamics Simulations of Laser Ablation in Covalent Materials — •Alexander Kiselev, Johannes Roth, and Hans-Rainer Trebin — Institut für Theoretische und Angewandte Physik, Universität Stuttgart, Germany

Non-equilibrium phenomena in highly excited covalent systems induced by strong laser radiation fields have received much attention in recent years. Despite of many theoretical and computational investigations these ultrafast processes are still not well understood. Here we use multi-million particle molecular dynamics simulations to study the laser ablation in covalently bonded materials. A combined self-consistent continuum-atomistic model [1] was applied for carrier-lattice interaction and electron-hole recombination processes. In addition, the temporal and spatial dependence of the exited carrier density was taken into account by fitting the interatomic forces to finite-temperature density functional theory calculations.

Both, spatially homogeneous and Gaussian distributed laser power densities have been carried out. In the first case the heat conduction in the system can be treated as one-dimensional. Furthermore, by using single- and double-pulse femtosecond laser irradiations the influence of the pulse shape on the ablation threshold has been investigated for a wide range of laser fluences.

[1] J.K. Chen, D.Y. Tzou, J.E. Beraun, Int. J. Heat Mass Transfer. 48, 501-509 (2005)