New short-lived isomers inY84

Abstract

Low-lying short-lived isomeric states have been investigated in $^{84}\mathrm{Y}$ by the $^{84}\mathrm{Sr}$($p,n$) reaction at ${E}_{p}=13.5$ MeV. The g factors were measured by applying the time-differential perturbed angular distribution method in an external magnetic field. The properties determined for the new isomers are ${E}_{x}=112.4$ keV, ${I}^{\ensuremath{\pi}}=({4}^{+}),{T}_{1/2}=79(2)$ ns, $g=+0.578(7);{E}_{x}=210.4$ keV, ${I}^{\ensuremath{\pi}}=({4}^{\ensuremath{-}}),{T}_{1/2}=292(10)$ ns, $g=+0.234(6)$. On the basis of the measured g factor, the $\ensuremath{\pi}1{g}_{9/2}\ensuremath{\bigotimes}\ensuremath{\nu}1{g}_{9/2}$ configuration has been assigned to the ${4}^{+}$ isomeric state. The low-lying states in $^{84}\mathrm{Y}$ were discussed within the two-quasiparticles plus rotor model. The ${4}^{\ensuremath{-}}$ isomeric state has been interpreted by the pure $\ensuremath{\pi}[301]3/2\ensuremath{\bigotimes}\ensuremath{\nu}[422]5/2$ configuration, which reproduces the experimental g factor at a prolate quadrupole deformation of ${\ensuremath{\varepsilon}}_{2}\ensuremath{\approx}0.16$.