Inelastic scattering in the [formula omitted] system leading to unbound excited states of either nucleus

Abstract

Complete angular distributions for elastic scattering and inelastic scattering to the first excited state (3+, 2.186 MeV) of 6Li and the second excited state (52−, 2.43 MeV) of 9Be in the system 6Li + 9Be are presented for energies Ecm. = 7, 10 and 12 MeV. The inelastic-scattering cross sections for these particle-unbound excited states are measured by detecting the corresponding recoil nucleus. The wide range of the inelastic-scattering angular distributions (30° ≲ θc.m. ≲ 170°) is achieved by interchanging appropriately the role of the projectile and target nuclei. Excitation functions for the studied elastic and inelastic scattering covering the energy range 4 ≲ Ec.m. ≲ 12 MeV are reported also. In the analysis, the channels with the nucleus 6Li excited and with the nucleus 9Be excited are coupled to the ground states in one coupled-channels calculation, using an optical potential with a real double-folded part and a Woods-Saxon imaginary part. The inelastic-scattering data are fitted using deformation lengths that exhibit some energy dependence and that approach at lower c.m. energies more closely those deduced from the B(E2) values. Compound-nucleus contributions to the observed cross sections are calculated using the Hauser-Feshbach formalism, but are found to be rather small in this system, except at backward scattering angles. In addition, the effect of elastic and inelastic triton transfers is examined by performing finite-range DWBA calculations and such contributions are found also to be unimportant.