  The isobaric yield ratios of the fragments produced in the neutron-rich 48Ca
and 64Ni projectile fragmentation are analyzed in the framework of a modified
Fisher model. The correlations between the isobaric yield ratios (R) and the
energy coefficients in the Weisz\"acker-Beth semiclassical mass formula (the
symmetry-energy term asym, the Coulomb-energy term ac, and the pairing-energy
term ap) and the difference between the chemical potentials of the neutron and
proton ({\mu}n-{\mu}p) are investigated. Simple correlations between
({\mu}n-{\mu}p)/T, ac/T, asym/T, and ap/T (where T is the temperature), and lnR
are obtained. It is suggested that ({\mu}n-{\mu}p)/T, ac/T, asym/T, and ap/T of
neutron-rich nuclei can be extracted using isobaric yield ratios for heavy-ion
collisions at intermediate energies.

Nuclear Theory;Nuclear Experiment