Study of high-spin states in odd sn isotopes

Level schemes of odd Sn isotopes (A = 109–117) have been studied by an in-beam spectroscopy method through (α, xn) reactions. High-spin states above the vh11/2 states were systematically observed. The level sequences show characteristics quite similar to those of adjacent even Sn isotopes. The level schemes are divided into two regions at about 2 MeV excitation from the vh11/2 states. The lower-energy region can be understood by particle-core coupling schemes, while the higher-energy region is interpreted by three-quasiparticle configurations of s1/2, d3/2, d5/2, g7/2 and h11/2 neutrons. Particle-core coupling schemes are discussed based on the neutron number dependence of the energy ratio (E15/2−−E11/2−)E2+.