Angular momentum effects in subbarrier fusion of 64Ni+100Mo.

Abstract

Angular momentum distributions ${\ensuremath{\sigma}}_{l}$ for the compound nucleus $^{164}\mathrm{Yb}$ were deduced from measurements of \ensuremath{\gamma}-ray multiplicity for all significant evaporation residues from fusion of $^{64}\mathrm{Ni}$ and $^{100}\mathrm{Mo}$. At the lowest bombarding energies the ${\ensuremath{\sigma}}_{l}$ extend to higher l values than do predictions of barrier-penetration models that include coupling of the principal inelastic channels, even if the coupling strengths are increased to match the experimental excitation function. Likewise, ${\ensuremath{\sigma}}_{l}$ from a real potential with an energy-dependent shape fitted to the excitation function fails to reproduce the experimental ${\ensuremath{\sigma}}_{l}$ distribution. Better success is achieved with models in which fusion occurs at large distances.