Z-dependent Barriers in Multifragmentation from Poissonian Reducibility   and Thermal Scaling
  We explore the natural limit of binomial reducibility in nuclear multifragmentation by constructing excitation functions for intermediate mass fragments (IMF) of a given element Z. The resulting multiplicity distributions for each window of transverse energy are Poissonian. Thermal scaling is observed in the linear Arrhenius plots made from the average multiplicity of each element. ``Emission barriers'' are extracted from the slopes of the Arrhenius plots and their possible origin is discussed. 
L. Beaulieu, L. Phair, L.G. Moretto and G.J. Wozniak (Nuclear Science   Division, Lawrence Berkeley National Laboratory, Ber...