Solid-liquid phase transitions optically investigated for distributions of metallic aggregates. absence of hysteresis for the smallest sizes

Melting and solidification temperatures for distributions of lead aggregates of very small sizes (mean radius = 42 Å, the minimum detectable radius being r = 23 Å) are reported. These new results show the existence of a limit temperature T L = 392K below which all the aggregates are solid. A discussion of the results for the melting point depression is given on the basis of a phenomenological approach. For the case of solidification, T L is compared to the stability limit temperature of the supercooled liquid predicted by a simple adiabatic nucleation model.