One-neutron transfer study of 137Xe and systematics of 13/21+ and 13/22+ levels in N=83 nuclei.

Excited states in 137Xe have been studied by using the near-barrier single-neutron transfer reactions 13C(136Xe, 12Cγ)137Xe and 9Be(136Xe,8Beγ)137Xe in inverse kinematics. Particle-γ and particle-γγ coincidence measurements have been performed with the Phoswich Wall and Digital Gammasphere detector arrays. Evidence is found for a 13/22¹ level (E=3137keV) and for additional high-lying 3/2- and 5/2- states. The results are discussed in the framework of realistic shell-model calculations. These calculations are also extended to the 13/21+ and 13/22+ levels in the N=83 isotonic chain. They indicate that there is a need for a value of the neutron 0i13/2 single-particle energy (ESPE=2366keV) lower than the one proposed in the literature. It is also demonstrated that the population patterns of the j=ℓ±1/2 single-particle states in 137Xe are different for the two targets used in these measurements and the implications of this effect are addressed. [ABSTRACT FROM AUTHOR]