SUPERHEATING OF PB(111)

Time-resolved reflection high-energy electron diffraction is used to study the laser-induced superheating of Pb(111). For a heating laser pulse width of approximately 180 ps, two regimes are observed depending upon the incident peak laser intensity. In the first regime, the time-resolved electron diffraction intensity indicates a transient superheating of the surface followed by cooling below the bulk melting temperature. In the second regime, which occurs at higher peak laser intensities, superheating is followed by melting. Superheating up to 120 K above the bulk melting temperature is observed.