Strong neutron-transfer coupling effects in the reaction mechanism of the 18O+64Zn system at energies near the Coulomb barrier

The precise quasielastic excitation function for the O-18 + Zn-64 system was measured at energies near and below the Coulomb barrier at theta(lab) = 161 degrees, from which its correlated quasielastic barrier distribution was derived. The excitation functions for the two-neutron, alpha, and tritium transfer reactions have also been measured at the same conditions. These data were well described by the coupled channel and coupled reaction channel calculations. The comparison of the data with theoretical calculations shows the strong influence of three inelastic channels in the coupling process: the quadrupole and octupole vibrational states of Zn-64, 2(1)(+) and 3(1)(-), and the quadrupole vibrational state of O-18, 2(1)(+). In addition, theoretical calculations indicate that the two-neutron stripping is mostly due to a one-step process, which has a striking effect on the reaction mechanism of this system.