Liquid-gas phase transition and instabilities in two-component systems with asymmetric interaction

The liquid-gas phase transition and associated instability in two component systems are investigated using a mean field theory. The importance of the roles of both the Coulomb force and the symmetry energy terms are studied. The addition of the Coulomb terms brings asymmetry into a mean field interaction and thus results in important differences with previous approaches, which did not include such terms. The asymmetric Coulomb effects modify the chemical instability and mechanical instability domains shifting many features, such as the line of equal concentration and the contact line of chemical and mechanical instability boundary, away from proton fraction point $y=1/2\mathrm{}$ to a value closer to the valley of $\beta$ stability. Thus, isospin fractionization is somewhat moderated by the presence of the Coulomb force. These features and characteristics of phase transition away from $\beta$ stability are discussed in detail.