The nucleus ${}^{49}\mathrm{Cr}$ has been studied using the reactions ${}^{28}\mathrm{Si}{(}^{28}\mathrm{Si},\alpha 2pn)$ at 115 MeV and ${}^{46}\mathrm{Ti}(\alpha ,n)$ at 12 MeV, respectively. A high-$K$ band with $K^{\pi }{=13/2\mathrm{}}^{+}$ has been identified, whose bandhead acts as an yrast trap for the low-lying levels with positive parity. This peculiar phenomenon is well reproduced by large-scale shell model calculations in the $\mathrm{pf}$ configuration space plus a proton hole in the ${1d}_{3/2}$ orbital. As an essential part of the work, lifetimes of some nonyrast states, as well as of a state in the $K^{\pi }{=5\mathrm{}}^{+}$ band in ${}^{50}\mathrm{Mn},$ have been determined using the Doppler shift attenuation method.

• Received 3 March 1999

DOI:https://doi.org/10.1103/PhysRevC.60.041305