Background: The evolution of and interplay between single-particle and collective excitations in the 40 $⩽N⩽$ 50 range for ${}_{38}$Sr and ${}_{40}$Zr isotopes have been studied.

Purpose: Measurement of the $g$ factor of the 2${}_1^{+}$ and 4${}_1^{+}$ states in radioactive ${}^{88}$Zr while simultaneously remeasuring the $g\left(2_1^{+}\right)$ factors in the Sr isotopes and extention of the measurements to higher energy states in the Sr isotopes. Lifetimes of states in these nuclei are determined.

Methods: The transient field technique in inverse kinematics and line-shape analysis using the Doppler-shift attenuation method are applied. The ${}^{88}$Zr nuclei were produced by the transfer of an $\alpha$ particle from the ${}^{12}$C nuclei of the target to ${}^{84}$Sr nuclei in the beam. The excited states in the stable ${}^{84}$Sr isotopes were simultaneously populated via Coulomb excitation by ${}^{12}$C in the same target. Coulomb excitation measurements on ${}^{86,88}$Sr were carried out with the same apparatus.

Results: The resulting $g$ factors and $B\left(E2\right)$ values of these nuclei reveal similarities between the two chains of Zr and Sr isotopes. Large-scale shell-model calculations were performed within the $p_{3/2},f_{5/2},p_{1/2},g_{9/2}$ orbital space for both protons and neutrons and yielded results in agreement with the experimental data.

Conclusions: In this paper the magnetic moments and lifetimes of several low-lying states in ${}^{88}$Zr and ${}^{84.86,88}$Sr have been measured and compared to large-scale shell-model calculations.

• Received 15 February 2012

DOI:https://doi.org/10.1103/PhysRevC.85.044322