Nuclear Fragmentation: Sampling the Instabilities of Binary Systems

We derive stability conditions of asymmetric nuclear matter (ANM) and discuss the relation to mechanical and chemical instabilities of general two-component systems. We show that the chemical instability may appear as an instability of the system against isoscalarlike rather than isovectorlike fluctuations if the interaction between the two constituent species has an attractive character as in the case of ANM. This leads to a new kind of liquid-gas phase transition, of interest for fragmentation experiments with radioactive beams.