Abstract
The low-lying states in and have been investigated by means of and isomer spectroscopy at the radioactive isotope beam factory (RIBF), respectively. A new isomer with a half-life of has been identified in . For the sequence of even-even Zr isotopes, the excitation energies of the first states reach a minimum at and gradually increase as the neutron number increases up to , suggesting a deformed subshell closure at . The deformed ground state of indicates that a spherical subshell gap predicted at is not large enough to change the ground state of to the spherical shape. The possibility of a tetrahedral shape isomer in is also discussed.
- Received 20 December 2010
DOI:https://doi.org/10.1103/PhysRevLett.106.202501
© 2011 American Physical Society