Determination of the spins and parities for the 0$^{+}_{4}$ and 0$^{+}_{5}$ states in 100Zr

Here, 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 100Zr utilizing γ-ray spectroscopy and γ–γ angular correlation techniques with the Gammasphere spectrometer, following the β– decay of neutron-rich, mass-separated 100,100mY isotopes. Comparisons with recent Monte Carlo shell-model 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 ≈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.