Relaxation of gaseous perturbations after evaporation of metals by nanosecond laser pulses

Abstract

The resistance of a lead sample was measured with very high accuracy from 295 K to the melting temperature 600.7 K. Up to about 540 K the resistance is determined by electron-phonon and electron-vacancy scattering with a vacancy formation enthalpy of 0.38 eV. Above 540 K there is an additional term in the resistance, well described by a thermally created defect with a formation enthalpy of 1.42 eV. While the vacancy formation entropy is approximately 1 . 6 k~ the formation entropy of the new defect is approximately 1 6 k~. This leads us to believe that the new defect has a liquid-like structure and consists approximately of a central atom or vacancy plus its nearest neighbours.