Isoscaling as a measure of Symmetry Energy in the Lattice Gas Model

The energetic properties of nuclear clusters inside a low-density, finite-temperature medium are studied with a Lattice Gas Model including isospin dependence and Coulomb forces. Important deviations are observed respect to the Fisher approximation of an ideal gas of non-interacting clusters, but the global energetics can still be approximately expressed in terms of a simple modified energy-density functional. The multi-fragmentation regime appears dominated by combinatorial effects in this model, but the isoscaling of the largest fragment in low energy collisions appears a promising observable for the experimental measurement of the symmetry energy.