Copper, gold, and platinum under femtosecond irradiation: Results of first-principles calculations

The paper investigates the interaction of femtosecond laser pulses with the thin films of copper, gold, and platinum. It considers electron-phonon relaxation processes and melting in the metal system nonequilibrium heated by laser radiation. Instead of the approximated formula by Wang et al. [Phys. Rev. B 50, 8016 (1994)], which is widely used to determine the temperature dependence of the electron-phonon coupling factor, we propose an improved approach for its more accurate calculation from first principles. Comparison with experiments and other calculations shows our approach to provide good calculation accuracy. Melting time versus absorbed energy density was estimated for the films and shown to be markedly sensitive to latent heat at low absorbed energy densities $(<1$ MJ/kg). Our calculations taken to study the temporal evolution of the (220) diffraction peak intensity after femtosecond irradiation show good agreement between experimental and theoretical data, which was attained due to higher accuracy in our determination of the temperature dependence electron-phonon coupling factor.