Single-particle and core-excited states in 49Sc : (II). The 48Ca(α, t) 49Sc reaction

Abstract

The 48Ca(α, t) 49Sc reaction has been studied at 36 MeV incident energy. About eighty levels have been observed up to 7.5 MeV excitation energy and angular distributions were measured from 6° to 58°, using a split-pole spectrometer. A local zero-range DWBA analysis has been carried out, and the deduced l-assignments and spectroscopic factors are compared with those obtained from the ( 3He, d) reaction. In the other hand, a large number of angular distributions cannot be reproduced by the DWBA calculations; they have been compared with the results of coupled-reaction-channel calculations, assuming two-step excitation of weak coupling states with a [ 48 Ca ∗ ⊗ f 7 2 ] structure. Good agreement between experimental angular distributions and two-step predictions is obtained for several 49Sc levels, suggesting spin and parity assignments. Moreover, as rather large cross sections are predicted for two-step excitations, it is concluded that, generally, these processes cannot be neglected in the analysis of (α, t) reactions.