Dresden 2017 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 5: Computational Materials Modelling: Materials at finite temperatures

MM 5.4: Vortrag

Montag, 20. März 2017, 11:00–11:15, IFW B

Dynamical Material Parameters in Molecular Dynamics Simulations of Laser Ablation — •Johannes Roth¹, Eugen Eisfeld¹, Stefan Scharring², Marco Patrizio³, Hans-Albert Eckel², and Mikhail Povarnitsyn⁴ — ¹FMQ, Universität Stuttgart — ²DLR Stuttgart — ³TU Darmstadt — ⁴JIHT, RAS Moskau

Laser ablation is studied with classical molecular dynamics simulations. The interaction of the laser with the free electrons in the metallic material is modeled with a two-temperature model with separate temperatures for the electrons and the atoms. The properties of the electrons, heat capacity and conductivity and the electron-phonon-coupling as well as the reflectivity of the laser are model as constants for femto-second pulses since they do not change during the short time of interaction. This assumption is no longer valid for pico- and nano-second pulses. We have implemented wide-range models for the electronic parameters similar to the work of Povarnitsyn [1] which describe the transition from the metal to the plasma state. The reflectivity is calculated dynamically with the Fresnel equations and the absorption with the help of the Helmholtz equations instead of the simple Lambert-Beer law. The improved results are compared to simulations carried out by hydrodynamic simulations.

[1] Povarnitsyn et al., Appl. Surf. Sci 258 (2012) 9480.