Nuclear expansion and symmetry energy of hot nuclei

D. V. Shetty, G. A. Souliotis, S. Galanopoulos, Z. Kohley, S. N. Soisson, B. C. Stein, S. Wuenschel, S. J. Yennello

Published 2008-02-05Version 1

The decrease in the symmetry energy of hot nuclei populated in $^{58}$Ni + $^{58}$Ni, $^{58}$Fe + $^{58}$Ni and $^{58}$Fe + $^{58}$Fe reactions at beam energies of 30, 40, and 47 MeV/nucleon, as a function of excitation energy is studied. It is observed that this decrease is mainly a consequence of increasing expansion or decreasing density rather than the increasing temperature. The results are in good agreement with the recently reported microscopic calculation based on the Thomas-Fermi approach. An empirical relation to study the symmetry energy of finite nuclei in various mass region is proposed.