A Study of the Effect of Alpha-Nucleus Potential on Alpha-Induced Transfer Reactions in the Sci-Shell.

Abstract

Effects of the molecular, normal optical Woods-Saxoo and squared Woods-Saxon (Michel) ~-nucleus potentials on the 27 Al(a.,tf1 Si. 21.l9.:w>Si(a.,d)30.31 ,32P and 21S(a.,p)31P reactions have been studied. The parameters of the molecular and Michel a.}' Al potential have been generated by fitting the a.-elastic data on 27 AI at the incident energy E«=64.5 MeV. The potential parameters of molecular, normal optical and Michel potential at Ea.=25 MeV have been determined by analyzing of ~-29.JOSi elastic data The elastic fits in these cases, seem to be of similar quality for all three forms of potentials. Full-finite range (FFR) distorted wave Born approximation (DWBA) calculatiom have been performed using the molecular, Michel and normal optical potentials to analyze the angular distributioos of cross-section for the 53 transitiom poJXllati.ng the bound and unbowtd states of 28Si via the (a.,t) reaction The molecular, Michel and optical potentials are found to produce satisfactory fits to the reaction data. For all the three potentials in the entrance channel, the deduced /-transfers for the transitions to the 15.02, 15.85 and 16.11 MeV states, differ from the assigmnents previously reported. The extracted spectroscopic factors are compared with shell-model predictions. FFR macroscopic and zero-range (ZR) microscopic distorted wave Born approximation calculations have been perfonned using molecular, namal optical and Michel potentials to analyze the angular distributioos of cross-sectioo for 12 transitions populating 0.0, 0.700, 1.454, 1.974, 2.538, 2.72, 2.84, 3.02, 3.93, 4.62, 5.42 and 7.20 MeV. states of 30p via the (a.,d) reaction Only the molecular potential has been able to reproduce satisfactorily the angular distribution and order of magnitude of cross-sections v for different transitions, but the normal optical potential is fotmd to be inadequate in accmm.ting the large angle data. The Michel potential is unsatisfact