Neutron-rich nuclei in the vicinity of the $N=40$ island of inversion are characterized by shell evolution and exhibit deformed ground states. In several nuclei isomeric states have been observed and attributed to excitations to the intruder neutron $1g_{9/2}$ orbital. In the present paper we searched for isomeric states in nuclei around $N=40,Z=22$ produced by projectile fragmentation at the Radioactive Isotope Beam Factory. Delayed $\gamma$ rays were detected by the Euroball RIKEN Cluster Array germanium detector array. High statistics data allowed for an updated decay scheme of ${}^{60}\mathrm{V}$. The lifetime of an isomeric state in ${}^{64}\mathrm{V}$ was measured for the first time in the present experiment. A previously unobserved isomeric state was discovered in ${}^{58}\mathrm{Sc}$. The measured lifetime suggests a parity changing transition, originating from an odd number of neutrons in the $1g_{9/2}$ orbital. The nature of the isomeric state in ${}^{58}\mathrm{Sc}$ is, thus, different from isomers in the less exotic V and Sc nuclei.

• Received 3 October 2020
• Revised 3 November 2020
• Accepted 24 June 2021

DOI:https://doi.org/10.1103/PhysRevC.104.014304