The115In(γ, γ′) reaction as a test of the quasi-particle phonon model with complex configurations in odd-mass nuclei

Abstract

The115In(γ, γ′) reaction was measured at the S-DALINAC using bremsstrahlung with endpoint energiesE 0=3.1, 4.6 and 5.2 MeV. In the excitation energy range of 1–5 MeV in total 32 transitions were observed, 18 of which were hithertoo unknown. The results are compared to two quasiparticle-phonon model calculations, one with a model space of ‘quasiparticle⊗phonon’ and one extended by ‘quasiparticle⊗two-phonon’ configurations. A substantial improvement is achieved in the description of low-lying115In states by the consideration of the more complex configurations. The calculations quantitatively account for the summed115In(γ, γ′) integrated cross sections and show a comparable amount of fragmentation of the individual transition strengths. The model interpretation of the microscopic structure of the experimentally observed transitions is discussed.