Interplay between proton and neutron s-bands in the Xe-Ba-Ce-region

Two-quasiparticle bands of positive parity (S-bands) in even-even nuclei in the Xe-Ba-Ce region are systematically examined. The equilibrium deformations for the ground-state band as well as for proton and neutron ( h 11 2 ) 2 configurations are obtained from total routhian surface (TR-surfaces) calculations. By comparing systematic trends of calculated and experimental crossing frequencies, attempts are made to assign the various bands as having an ( h 11 2 ) 2 neutron or proton character, respectively.