Coexistence of Vibrational and Quasiparticle Structures in Neutron-Deficient 114,115,116,117Te

Abstract

Excited states in 114-117Te were populated in the bombardment of 114,116Sn targets with 3He ions at energies Elab = 20.9-27.5 MeV. The subsequent de-excitation was studied using in-beam spectroscopic methods, including measurements of γ-ray excitation, γ-γ coincidences, γ-RF timing, γ-ray angular distributions and conversion electrons. States with angular momenta up to J ≲ 12 h were observed, but no isomers with T1/2 ≳ 1 ns were located. The excited structures are discussed in terms of vibrational bands coupled to one- and two-quasiparticle shell-model structures. The systematical behaviour of the excited states in Te isotopes is studied in the mass range A = 115-123 for the odd, and A = 112-134 for the even isotopes.