Superdeformation in bismuth

Abstract

High angular momentum states in $^{195\mathrm{\ensuremath{-}}197}\mathrm{Bi}$ are populated in two reactions: $^{183}\mathrm{W}$${(}^{19}$F,xn${)}^{202\mathrm{\ensuremath{-}}\mathit{x}}$Bi and $^{181}\mathrm{Ta}$${(}^{20}$Ne,xn${)}^{201\mathrm{\ensuremath{-}}\mathit{x}}$Bi at beam energies of 108 and 123 MeV, respectively. Gamma rays were detected using the Gammasphere array. Three weakly populated rotational sequences have been found. They each have properties characteristic of other superdeformed bands in this mass region. On the basis of cross-bombardment information we believe that one band belongs to each of $^{195}\mathrm{Bi}$, $^{196}\mathrm{Bi}$, and $^{197}\mathrm{Bi}$. The properties of the bands in the odd-Bi nuclei are best reproduced if the odd proton occupies the favored signature of the [651]1/2 orbital, while the band in $^{196}\mathrm{Bi}$ has this same proton configuration coupled to an additional N=7 (${\mathit{j}}_{15/2}$) neutron. The relative behavior of the ${\mathfrak{J}}^{(2)}$ moments of inertia can be qualitatively understood in terms of Pauli-blocking effects. \textcopyright{} 1996 The American Physical Society.