Nonequilibrium electron dynamics in materials driven by high-intensity x-ray pulses

摘要

We calculated the evolution of the electron system in solid-density matter irradiated by high-intensity x-raynpulses between 2 and 8 keV using molecular dynamics. For pulses shorter than 40 fs, the kinetic energy distributionnof the electrons is highly nonthermal during and right after the pulse, and a large fraction of the absorbed x-raynenergy resides with the fast photoelectrons which equilibrate on the timescale of the pulse length. The averagenionization and electron temperature of the bulk of the electrons are significantly lower than their equilibriumnvalues.