S. Pilotte

High-spin proton and neutron intruder configurations in 106Cd

Abstract High-spin states in 106Cd have been studied with the reactions 94Zr(16O, 4n)106Cd and 76Ge(34S, 4n)106Cd. A rotational band, based on a two-quasineutron (h 11 2 ) 2 configuration, is observed from its 10+ bandhead to spin 28 Ħ. This structure undergoes a band-crossing at a rotational frequency of approximately 0.45 MeV /Ħ, interpreted as the alignment of a pair of g 7 2 neutrons. Time-correlated spectroscopy has been used to identify states above the previously observed 12+ isomer at 4660 keV. These include a weakly populated, strongly coupled structure which indirectly feeds the isomer, and whose alignment and in-band decay properties are consistent with a deformed ν( h 11 2 ) 2 π( g 9 2 g 7 2 ) , four-quasiparticle configuration. The results are discussed in terms of cranked-shell-model and total-routhian-surface calculations. No evidence is found for a reported 16+ isomer at 7119 keV.

High-spin states in odd-odd 164Lu

Abstract High-spin states in odd-odd 164 Lu have been studied using 19 F and 23 Na induced fusion-evaporation reactions. Three strongly coupled rotational bands have been established and three decoupled bands were tentatively assigned to 164 Lu. The band crossing frequencies, energy sig-nature splittings, and relative transition probabilities were deduced from experimental data and compared with neighboring even-even and odd- A nuclei. An anomalously large band crossing frequency was observed in the excited band, and a pronounced signature inversion was observed in the yrast band of 164 Lu. These anomalies may be associated with residual neutron-proton interactions.

Quasicontinuum ridges in {sup 173,174}W

A strong quasicontinuum ridge with a spacing of 58.1 {plus_minus} 0.3 keV was observed in {sup 173}Wand {sup 174}W when populated at high spin. The ridge is a factor of 4 times more intense than that of the sum of discrete bands over the same range of rotational frequencies. The strength of the ridge may be due to the large number of nearly degenerate proton orbitals lying above the {ital Z} = 73 gap occurring at a deformation {beta}{sub 2}{approx_equal}0.3. {copyright} {ital 1996 The American Physical Society.}