Intermediate mass fragment production in central collisions of intermediate energy heavy ions

We present Z distributions for fragments with 1≤Z≤12 from central collisions of ${}_{}{}^{40}{}_{}{}^{}$ Ar${+}^{45}$Sc at incident energies ranging from 35 to 115 MeV/nucleon. We find that the Z distributions can be described by a power law or an exponential and steepen with increasing incident energy. Over the range of incident energies studied, the average number of intermediate mass fragments decreases while the average number of particles increases. When combined with previous results for the charge distributions, a minimum is observed in the extracted power-law parameter.