G. D. Johns

First observation of a strongly-coupled band in even-even A ≈ 80 nuclei: 76Kr

Abstract A new ΔI = 1 band has been discovered in 76Kr, the first to be observed in an even-even A ≈ 80 nucleus. The rotational band is built upon a Kπ = 4(+) state at 2844 keV excitation energy which is interpreted as a strongly-coupled two-quasineutron configuration ( [301] 3 2 − ⊗ [303] 5 2 − )4+ at a prolate deformation of π2 ≈ 0.34.

Nuclear structure of neutron-rich 78 As

Excited states in the neutron-rich doubly-odd nucleus78As have been identified for the first time by proton-γ and γ-γ coincidence measurements via the76Ge(α, pn) reaction at 32, 36, and 40 MeV beam energy. Four levels have been found to decay with lifetimes in the nanosecond region. The 5(+) to (10+) states are ascribed to the (πg9/2⊗νg9/2) intruder two-quasiparticle configuration with some collective components in the 9(+) and (10+) states.

Weak coupling in [sup 143]Nd

High-spin states of [sup 143]Nd have been studied using the [sup 130]Te([sup 18]O,5[ital n]) reaction at 85 MeV. The yrast states observed up to a tentatively assigned spin of 45/2 can be described in a remarkably simple way by the weak coupling of an [ital f][sub 7/2] neutron to the [sup 142]Nd core nucleus. Our results demonstrate that [sup 143]Nd is one of the best known examples of weak coupling at high angular momentum.

Possibleπ(h 11 2/3 g 7 2/−1 ) states in144Nd

High spin states of the nucleus144Nd have been studied using the techniques of gamma-ray spectroscopy and the130Te(18O,4n) reaction at 85 MeV. It is suggested that a sequence of states having J=17–24 arises from the coupling of the h12/3g72−1 proton configuration to the f72/2 and f7/2h9/2 neutron configurations.