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

J. Wu, M. P. Carpenter, F. G. Kondev, R. V. F. Janssens, S. Zhu, E. A. McCutchan, A. D. Ayangeakaa, J. Chen, J. Clark, D. J. Hartley, T. Lauritsen, N. Pietralla, G. Savard, D. Seweryniak, V. Werner

Published 2024-02-04, updated 2024-02-06Version 2

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.