Molecular dynamics simulation using pair and many body interatomic potentials: ultrashort laser ablation of Fe

Abstract

The influence of the pair Morse potential and the embedded-atom method (EAM) based potential on the description of the properties and the ultrashort laser ablation process of Fe by molecular dynamics (MD) simulation technique is studied. The accuracy of both potentials in evaluation of the melting temperature, the linear thermal expansion coefficient and the compression behavior of Fe is estimated. The EAM potential is found to give more precise description of the properties of Fe than the Morse one. The melting temperature is overestimated only 2% in the case of EAM and 24% for the Morse potential, respectively, compared to the experimental value. A discrepancy in the presentation of the elastic properties is also observed, as it is more pronounced in the case of Morse potential.The MD simulation of laser ablation of iron is performed for ultrashort laser pulses (λ=800nm) with duration of 100fs and at fluences below the ablation threshold up to 1J/cm2. Analysis of the mechanism of ablation, evolution of the process, the temperature and the pressure distributions in the material is made.