High-spin state spectroscopy in Tb-143 - art. no. 054304

The Tb-143 nucleus has been studied with the Mo-92 (Fe-54, 3p gamma) reacti on at 240-MeV incident energy, extending the systematics of odd-A, N = 78 i sotones to higher Z. For the yrast band, excited states up to a spin of 59/ 2(-) have been observed. The first allowed backbend occurs at a rotational frequency of (h) over bar omega = 0.38 MeV. Three- and five-quasiparticle s tructures were identified, similar to those seen in lower mass N = 78 isoto nes. Two of these structures have characteristics typical of mixed proton-n eutron oblate configurations with one pair of aligned h(11/2) neutrons. In addition, two bands consisting of stretched E2 transitions have been observ ed with no known analogous structures in neighboring nuclei. The results ar e discussed in terms of the cranking model. [S0556-2813(99)03310-5].