We report on the measurement of level energies, lifetimes, γ-ray intensities, and angular distributions in ${}_{}{}^{73}{}_{}{}^{}\mathrm{Br}$, obtained in the reactions ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${(}^{36}$Ar,3p) and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${(}^{40}$Ca,α3p). The g factor of the 241 keV isomeric state (τ=50 ns) was determined to be g=1.31(9) from the Larmor precession in an external magnetic field. The fully aligned members of a rotationally aligned $g_{9/2}$ band were identified up to spin $I^{\pi }$${=(33/2\mathrm{}}^{+}$; the E2 transition strengths indicate a large prolate deformation decreasing from ${\beta }_2$=0.37(4) to ${\beta }_2$=0.33 at rotational frequency ħω≊0.45 MeV. The negative parity yrast bands with signatures α=±1/2 were established up to a probable spin of ${(37/2\mathrm{}}^{\mathrm{-}}$. The α=+1/2 yrast band shows a one quasiparticle to three quasiparticle band transition at the same frequency, probably associated with the alignment of two $g_{9/2}$ protons. The structure of ${}_{}{}^{73}{}_{}{}^{}\mathrm{Br}$, which is very similar to that of ${}_{}{}^{75}{}_{}{}^{}\mathrm{Br}$, has been interpreted with the Strutinsky-Bogolyubov cranking and deformed configuration mixing models.

• Received 10 July 1987

DOI:https://doi.org/10.1103/PhysRevC.36.2409