Mass dependence of temperature for intermediate mass fragment in heavy-ion reactions

An A-dependent temperature has been found both for the primary fragments and for the measured fragments in an improved isobaric-yield-ratio-difference method, which obeys the function $T=C(1-k\cdot A)$, with C and k being parameters. Within the finite temperature range, the A-dependence of the difference among the free energy and binding energy is found to depend on A in the form of $y=1/C(1-k\cdot A)$. For the measured fragment, the temperature obtained by the improved isobaric-yield-ratio-difference method depends on A in the manner of $T=1/C(1-k\cdot A)$ within $T⩽$ 4 MeV. The A-dependence of temperature can be explained by the A-dependence of the isobaric difference among free energy in a natural way. (paper)