Authors: L.V. Zhigilei and B.J. Garrison
Affilation: Penn State University, United States
Pages: 65 - 68
Keywords: molecular dynamics simulation, laser ablation, mesoscopic model, pressure waves, non-reflecting boundary condition
A breathing sphere model has been developed for molecular dynamics simulations of laser ablation of organic solids. The novel feature of this model is an approximate representation of the internal molecular motion, which permits a significant expansion of the time and length scales of the model, and yet still allows one to reproduce a realistic rate of the vibrational relaxation of excited molecules. A dynamic boundary condition that accounts for the laser induced pressure wave as well as the direct laser energy deposition in the boundary region allows one to focus the computational effort to the region where active processes of laser ablation and damage occur. The model has been applied to study the mechanisms of laser ablation of molecular solids, velocity distributions of ejected molecules, and laser damage in the case of spatially localized absorbers. The results for different laser fluences and pulse durations have been analyzed and related to available experimental data.