Properties of ^{187}Ta Revealed through Isomeric Decay.

Mass-separated ${^{187}\mathrm{Ta}}_{114}$ in a high-spin isomeric state has been produced for the first time by multinucleon transfer reactions, employing an argon gas-stopping cell and laser ionization. Internal $\ensuremath{\gamma}$ rays revealed a ${T}_{1/2}=7.3\ifmmode\pm\else\textpm\fi{}0.9\text{ }\text{ }\mathrm{s}$ isomer at $1778\ifmmode\pm\else\textpm\fi{}1\text{ }\text{ }\mathrm{keV}$, which decays through a rotational band with perturbations associated with the approach to a prolate-oblate shape transition. Model calculations show less influence from triaxiality compared to heavier elements in the same mass region. The isomer-decay reduced $E2$ hindrance factor ${f}_{\ensuremath{\nu}}=27\ifmmode\pm\else\textpm\fi{}1$ supports the interpretation that axial symmetry is approximately conserved.