Transfer of neutron-proton pairs in heavy-ion interactions

Neutron-proton transfer reactions have been studied on12C,13C,14N,15N,16O and20Ne targets in the (11B,9Be) reaction induced by 116 MeV11B ions. The reactions are characterized by a high degree of selectivity, and evidence has been obtained for a particularly simple direct mechanism involving simultaneous surface transfer of the nucleon pair. TheT = 1 reaction channel is significantly inhibited, and the reaction spectra and angular distributions are similar to those of the corresponding alpha-particle-induced neutron-proton transfer reactions. DWBA calculations including finite range and full recoil reproduce the observed angular distributions, and a Hauser-Feshbach analysis confirms the dominant direct character of these reactions.