Melting of free sodium clusters

Abstract.

Heat capacities have been measured across the solid to liquid phase transition for free, mass selected sodium cluster ions, Na⁺ _n , with 55≤n≤199. Results for the melting point and the latent heat of fusion are presented here. The melting points are about 30% lower than the bulk value, and show large variations (±50 K). They seem to be highest in a mass range, where both an icosahedral and an electronic shell closing occurs.