Dynamical aspects of isoscaling

The origin and dynamical evolution of isoscaling was studied using classical molecular dynamics simulations of 40Ca + 40Ca, 48Ca + 48Ca, and 52Ca + 52Ca, at beam energies ranging from 20 MeV/A to 85 MeV/A. The analysis included a study of the time evolution of this effect. Isoscaling was observed to exist in these reactions from the very early primary isotope distributions (produced by highly non-equilibrated systems) all the way to asymptotic times. This indicates that isoscaling is independent of quantum effects and thermodynamical equilibrium. In summary, collision-produced isoscaling appears to be due more to the mere partitioning of the proton-neutron content of the participant nuclei, than to specific details of the reaction dynamics.