Formation and decay of 164Yb* in near- and below-barrier fusion reactions.

Abstract

A consistent description of the formation and decay of $^{164}\mathrm{Yb}^{\mathrm{*}}$ in the fusion of $^{16}\mathrm{O}$${+}^{148}$Sm and $^{64}\mathrm{Ni}$${+}^{100}$Mo is presented in a bombarding energy range from near to well below the entrance channel Coulomb barrier. Fusion excitation functions and angular momentum distributions are described well with a recently proposed one-dimensional barrier penetration model with energy-dependent fusion barriers. The main features of fusion and angular momentum distribution data in $^{64}\mathrm{Ni}$${+}^{100}$Mo are also reproduced with simplified coupled channel calculations. The statistical model accounts well for the decay of $^{164}\mathrm{Yb}^{\mathrm{*}}$ in the $^{16}\mathrm{induced}$ reaction and for most of the data in the $^{64}\mathrm{induced}$ reaction. The evaporation residue fractional cross sections as a function of the compound nucleus excitation energy show trends that correlate with the low- and high-spin regions of the compound nucleus angular momentum distributions populated in the two reactions.