[en] The authors have performed time-resolved spectroscopic measurements specifically aimed at the study of excitation conditions reached in silicon and germanium just prior to the melting of the surface with 20-ps 0.532-μm laser pulses. Since the photon energy is large compared to the band gap in germanium, side effects such as saturation of the absorption and intervalence band transitions which complicate interpretation of the results are avoided. The delayed probe beam is obtained by Raman shifting the fundamental frequency, 1.06μm, in high-pressure H/sub 2/ and CH/sub 4/ gas cells. The reflectivity and transmission at 1.9 μm vs pump fluence F/sub 2→ are shown for a delay time of 20 and 200 ps, respectively. The experimental data (circles) are compared to the calculated response (continuous lines) derived from numerical simulations of the carrier density and temperature based on the thermal model, which assume the Auger effect as the main carrier recombination mechanism. Under degenerate conditions a higher fraction of available energy is routed to the carrier gas rather than directly to the lattice. Thus significant heating of the lattice occurs at later times via recombination and subsequent phonon emission