Fig. 4

Time evolution of the electron temperature. The data deduced from time-resolved XAS measurements (full circles) are compared with the two-temperature hydrodynamic calculation (plain line). The calculated ion temperature is also plotted (dashed line). The incident fluence is 1 J cm⁻². The experimental data indicate a rise-time of 75 ± 25 fs (line and shadowed area in the inset). The gradual decrease observed at longer time is well reproduced by the model and is understood as the electron−ion thermal equilibration. Error bars are calculated from the integrated standard deviation within the pre-edge in the XAS data series