Pi h11/2 intruder and pi g9/2-1 strongly coupled bands in 115Sb.

Abstract

High spin states have been populated in $^{115}\mathrm{Sb}$ with the reaction $^{100}\mathrm{Mo}$${(}^{19}$F,4n${)}^{115}$Sb at a beam energy of 82 MeV. Two intruder rotational bands (\ensuremath{\Delta}I=2) extending to spins 43/${2}^{\mathrm{\ensuremath{-}}}$ and 51/${2}^{\mathrm{\ensuremath{-}}}$ have been observed. The extracted relative B(E2) value supports the nearly diabatic nature of these two bands. The transition energies in these two bands are nearly similar and the bands have a relative spin alignment of 4\ensuremath{\Elzxh} at low frequencies. The bands have been interpreted to be based on the \ensuremath{\pi}${\mathit{h}}_{11/2}$ orbital coupled to the deformed 2p-2h states of the $^{114}\mathrm{Sn}$ core. Possible quasiparticle configurations for the excited negative parity band are discussed and it is suggested that this band is based on aligned ${\mathit{h}}_{11/2}$ neutrons, the yrare extension of which is observed diabatically down to very low spin values. Two strongly coupled (\ensuremath{\Delta}I=1) rotational bands involving the (\ensuremath{\pi}${\mathit{g}}_{9/2}$${)}^{\mathrm{\ensuremath{-}}1}$ configuration have been observed, of which the known strongly coupled band has been extended from 23/${2}^{+}$ to 37/${2}^{+}$ in spin and the extracted B(M1;I\ensuremath{\rightarrow}I-1)/B(E2;I\ensuremath{\rightarrow}I-2) values for this band are compared with the D\"onau-Frauendorf formula. Alignment features due to the ${\mathit{h}}_{11/2}$ neutrons in the observed bands are compared with the core nucleus $^{114}\mathrm{Sn}$ and cranked shell model calculations. Equilibrium deformations for a range of odd Sb isotopes have been calculated with various intrinsic proton configurations. \textcopyright{} 1996 The American Physical Society.