Excitation and relaxation of nonthermal electron energy distributions in metals with application to gold

A semiempirical theory for the excitation and subsequent relaxation of nonthermal electrons is described. The theory, which applicable to ultrafast-laser excited metals, based on Boltzmann transport equation carrier distribution function $f(\ensuremath{\epsilon},t)$ includes electron-phonon, electron-electron, electron-photon scattering integrals in forms that explicitly depend electronic density states. Electron-phonon coupling treated by extending Allen [Phys. Rev. Lett. 59, 1460 (1987)] include highly-excited electron distributions, used determine energy transfer rate between a subsystem thermal phonon subsystem. Electron-electron with simple energy-conserving electron-electron integral. integral assumes photon absorption assisted. We apply analyze prior ultrafast thermionic emission, two-color photoemission, inelastic light (Raman) experiments Au. These analyses show getting details necessary proper interpretation each experiment. Together, photoemission Raman-scattering indicate an 1 eV above Fermi level has time range 25 55 fs.