Abstract
Gamma-ray spectra of neutron-deficient isotopes between Ce (Z = 58) and Gd (Z = 64) have been investigated. New bands of states were identified in many even--even, odd--A, and odd--odd nuclei. Results on the ground-state bands in the even--even nuclei exp 126 sub 58 Ce sub 68 , exp 128,130,132 sub 60 Nd sub 68,70,72 , exp 134,136 sub 62 Sm sub 72,74 , and exp 138,140 sub 64 Gd sub 74,76 are reported. The systematic trends of deformation are presented and compared with theoretical predictions. The lightest isotopes appear to be axially symmetric rotors with epsilon sub 2 = > 0.3. 22 ref.--AA