Molecular dynamics study of solid melting and vaporization by laser irradiation

The molecular processes of the phase change of melting and vaporization of solid materials by laser beam irradiation were studied numerically by using the molecular dynamics method. By absorbing the laser light energy, the solid atoms or molecules are excited in the interatomic or intermolecular potential energy to change their interacting forces. The resulting Hamiltonian equations of atomic or molecular motions are solved with the molecular dynamics method to understand the molecular behavior of the phase changing process. The excitation strength, that is, the laser energy of irradiation, has the most predominant effect on the phase change of vaporization and melting. The laser energy absorbed is converted to the kinetic energy of the evaporating particles and that of the lattice particles. This process of energy transfer is controlled by the irradiation period as well as the excitation life.