Excited States of 31P and 32S Studied in the (p, p') Reaction at 185 MeV

The inelastic scattering of protons from targets of natural phosphorus and sulphur has been studied at 185 MeV with a total energy resolution of 370 keV. New spin-parity assignments have been made for some levels in 31P and 32S on the basis of an analysis in the plane wave impulse approximation and on considerations based on the applicability of the excited core model. The concepts of this model also explained a systematic appearance of strongly populated levels in the two nuclei. Relative transition strengths have been extracted for the strongest transitions observed. The results are qualitatively discussed within the frameworks of the collective rotor and vibrator models and the shell model. The importance of particle-hole excitations in inelastic proton scattering from 31P and 32S is displayed by a comparison with results of appropriate stripping and pick-up experiments.