Inelastic scattering of 40 MeV protons fromMg24. II. Microscopic calculations for positive parity states

Abstract

Proton inelastic scattering data at 40 MeV bombarding energy are compared to microscopic distorted-wave Born-approximation calculations for positive parity states in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ utilizing shell-model wave functions spanning the full $2s1d$ shell basis. Both empirical forces and forces derived from free nucleon-nucleon potentials are used in the calculations. Except for four transitions for which strong coupling effects are evident, the agreement between theory and experiment is quite good. Enhancement factors extracted for the natural parity transitions are consistent with the effective charges obtained from electromagnetic transition rates. Levels corresponding to the giant $M1\mathrm{}$ resonance in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ have been resolved in the present experiment. The fact that the renormalization factor between theory and experiment is close to unity for the 10.713 MeV 1+; $T=1\mathrm{}$ state indicates that little or no renormalization of the two-body force is necessary for this inelastic transition. It is argued that little renormalization is also involved for magnetic-type inelastic transitions of multi polarities higher than $M1\mathrm{}$.