Clusterization in low and intermediate density nuclear matter in the modified nuclear statistical equilibrium model

Abstract

The formation of light and intermediate clusters in low and intermediate density nuclear matter is investigated within the modified nuclear statistical equilibrium model. We include clusters up to mass number A=61 and densities up to 0.1 nucleons fm−3. The original nuclear statistical equilibrium model is modified by using density-dependent cluster binding energies. Whereas the light clusters are dominant at very low densities, it is found that the intermediate clusters become dominant at higher densities. As the temperature increases the dominance of the lighter clusters grows at the expense of the heavier clusters. We also evaluate the equation of state of nuclear matter within this model and determine that the critical temperature is 12.5 MeV, well below the values predicted by other equations of state. Finally we calculate the fragment multiplicity distribution within this model and find that its derivative with respect to temperature dM/dT has a maximum at a temperature (the liquid–gas transition temperature) close to that expected by other calculations.