Two 0$^{ +}$ states at 1294.5 and 1774.0 keV, together with three 2$^{ +}$ and one 4$^{ +}$ levels, were identified or unambiguously spin-parity assigned for the first time in $^{ 100}$Zr utilizing $\gamma$-ray spectroscopy and $\gamma$-$\gamma$ angular correlation techniques with the Gammasphere spectrometer, following the $\beta^{ -}$ decay of neutron-rich, mass separated $^{ 100,100m}$Y isotopes. Comparisons with recent Monte Carlo Shell-Model (MCSM) calculations indicate that these two states are candidates for the bandhead of a sequence in a shape-coexisting spherical minimum predicted to be located around $\approx$1500 keV. According to the measured relative B(E2)$_{ relative}$ transition probabilities, the 0$_{ 5}^{ +}$ state exhibits decay properties which more closely align with those predicted for a spherical shape, while the 0$_{ 4}^{ +}$ level is suggested to be associated with a weakly-deformed shape similar to one related to the 0$_{ 2}^{ +}$ state.
Categories: nucl-ex