Shell model and octupole states in148Gd from in-beam experiments

摘要: Through (α, 4n) and (τ, 3n) reactions the high-spin states in two-neutron nucleus148Gd were populated up toIπ=21− at 7.2 MeV, including numerous above yrast line. The148Gd energy spectrum is interpreted terms of spherical shell model. Identification (νf7/2i1 3/2)10− state gives νi13/2 single particle free octupole admixtures as 2.1(1) MeV. Eight between 1.2 3.7 MeV identified couplings two valence-particles to the146Gd phonon, three above-lying levels are assigned double-octupole excitations a 12+ which decays by anE3-E3 stretched cascade. All these can be quantitatively predicted from one-particle x phonon of147Gd. The 3 four-quasiparticle ofπ+1π−1ν2 andπ2ν2 type their energies good accord with model estimates.