Coexisting structures in 115Sn and 116Sn

Excited states up to I ≈ 20 in 115Sn and 116Sn, populated via the (18O, αxn) reactions, have been studied using the DORIS Ge detector array in conjunction with charged particle detectors. In both nuclei, spherical as well as regular, deformed level structures were found. The spherical states are interpreted to arise from pure neutron configurations, while the deformed, intruder bands obviously involve proton 2p - 2h excitations across the Z = 50 shell gap. © 1998 Elsevier Science B.V.