Angular correlation and coincidence studies of excited 0/sup +/ and other levels in the transitional Ce nuclides /sup 142/Ce, /sup 144/Ce, /sup 146/Ce, and /sup 148/Ce

The decays of the neutron-rich nuclides /sup 142/La, /sup 144/La, /sup 146/La and /sup 148/La to the levels of the transitional nuclides /sup 142/Ce, /sup 114/Ce, /sup 146/Ce and /sup 148/Ce, respectively, have been studied using mass-separated sources. Angular correlation studies have been employed to identify new excited 0/sup +/ levels in /sup 146 /Ce and support spin and parity assignments for 1/sup -/, 3/sup -/, 2 /sup +/, 3/sup +/, 4/sup +/ and 6/sup +/ levels in /sup 144/Ce and /sup 146/Ce. An excited 0/sup +/ level in /sup 148/Ce is indicated by coincidence ratios and electron studies, while no clear evidence can be found for the location of an excited 0/sup +/ level below 2 MeV in /sup 144/Ce. The resulting isotonic and isotopic systematics are discussed in terms of the transition from the closed shells at N=82 and Z=50 to the region of deformed nuclides. (13 refs).