Clustering and thermodynamics in small systems

We address the problem of mapping clustering and thermodynamics in simple f luids. We predict the existence of self-bound clusters of particles in the supercritical phase. In the thermodynamic limit, these clusters generate a percolation line that starts at the critical point. The cluster size distri bution also changes suddenly in the vicinity of the liquid-gas coexistence line at sub-critical densities. The internal temperature of these clusters is lower than the global temperature of the system. In small systems, these results remain qualitatively valid. We discuss its relevance to the proble m of the fragmentation of atomic nuclei or atomic clusters.