Scattering of -particles and He on O nuclei and its excitation mechanism at energies near 50MeV.

Elastic and inelastic scattering of -particles at 48.1MeV and 3He at 60MeV on O nuclei has been measured with excitation of states at 6.05 (0)-6.13 (3)MeV, 6.92 (2)-7.12 (1)MeV and 8.87 (2)MeV. The center-of-mass beam momenta are the same for these two strongly absorbed particles. Analysis of angular distributions was performed in the frameworks of the optical model, the coupled channels method and the Distorted Wave Born Approximation (DWBA). A good description of experimental data was obtained over the full angular range without taking into account the spin-orbit interaction and the cluster transfer mechanism with real potentials that have volume integrals of about 400MeV fm3. Collective and microscopic models were used in the analysis of the inelastic scattering. The values of the octupole deformation lengths were extracted. It is shown that nuclear rainbow effects appear not only in the elastic, but also in the inelastic scattering with excitation of the 3 state of O. [ABSTRACT FROM AUTHOR]