Inelastic α-particle scattering on doubly even selenium isotopes

Abstract

Elastic and inelastic scattering of 25 MeV alpha particles by isotopically enriched targets of 76.78.80Se have been measured. Results have been analysed in the coupled-channel framework on the basis of two collective models: the harmonic vibrational model and the asymmetric rotational model. Deformation parameters were extracted for the first quadrupole and octupole states in each nucleus and compared with similar quantities obtained from other scattering experiments and Coulomb excitation measurements. Departure of the gamma parameter from the value deduced from the energy ratio E(22+)/E(21+) in the inelastic scattering of polarised protons by Matsuki et al (1983) is also indicated by the authors' data. The asymmetric rotational model provides a better description of the even-parity states than the harmonic vibrational model.