Transfer, sequential decay, and quasi-free reactions induced by 18-MeV He beam on Li, Li, and C

The He + Li and He + C scattering and reactions have been studied using an 18-MeV He beam. Experimental results for the elastic scattering on all three targets are in fair agreement with optical model predictions, using the potentials found in the analysis of the Li scattering on the same targets and at close beam energies. Several two-body exit channels show clear signatures of a direct reaction mechanism allowing extraction of spectroscopic information. The measured angular distribution for the He + Li → α + Li reaction indicated close similarity between the α + 2n configuration in He and the α + d configuration in Li. The obtained results for α-particle pickup from both Li and Li give large values of α spectroscopic factors for some Be states, indicating their well-developed α + He cluster structure. The exotic two-proton pickup reaction (He, Be) was studied, as well as two-neutron and triton transfer reactions. Quasi-free scattering of He on deuteron and α particle in Li was also observed. The sequential decay reactions He + Li → He + α + d, He + Li → 2α + t + n, He + Li → He + α + t, and He + C → Be + 2α were clearly seen, and α clustering of some states in Li, Be, and C was thus studied. Several new spectroscopic results obtained for some Be states support the existence of a molecule-like rotational band in Be with a very large moment of inertia.