Rotational band properties of173W

Abstract

High-spin states in ${}^{173}$W have been studied using the ${}^{150}$Nd(${}^{28}\text{Si},5n$)${}^{173}$W reaction at beam energies of 135 and 140 MeV. The previously known bands associated with the $7/{2}^{+}[633]$, $5/{2}^{\ensuremath{-}}[512]$, and $1/{2}^{\ensuremath{-}}[521]$ configurations are extended significantly, and the unfavored signature branch of the $1/{2}^{\ensuremath{-}}[521]$ band is established for the first time. The band properties, such as level spacings, band-crossing frequencies, alignment gains, and signature splittings, are discussed with an emphasis on the low-spin signature inversion observed in the $5/{2}^{\ensuremath{-}}[512]$ band. By comparing the experimental $B(M1)/B(E2)$ ratios with the theoretical values, we conclude that the configuration of the $5/{2}^{\ensuremath{-}}[512]$ band is quite pure at low spins without appreciable admixture of the $5/{2}^{\ensuremath{-}}[523]$ orbit, in conflict with the particle rotor model calculated results.