FORMATION AND DECAY OF YB-164 ASTERISK IN NEAR-BARRIER AND BELOW-BARRIER FUSION REACTIONS

A consistent description of the formation and decay of 164Yb in the f usion of O-16 + Sm-148 and 64Ni + Mo-100 is presented in a bombarding energy range from near to well below the entrance channel Coulomb barr ier. Fusion excitation functions and angular momentum distributions ar e described well with a recently proposed one-dimensional barrier pene tration model with energy-dependent fusion barriers. The main features of fusion and angular momentum distribution data in 64Ni + Mo-100 are also-reproduced with simplified coupled channel calculations. The sta tistical model accounts well for the decay of 164Yb in the O-16-induc ed reaction and for most of the data in the 64Ni-induced reaction. The evaporation residue fractional cross sections as a function of the co mpound nucleus excitation energy show trends that correlate with the l ow- and high-spin regions of the compound nucleus angular momentum dis tributions populated in the two reactions.