The nu 9/2[404] orbital and the deformation in the A similar to 100 region

摘要

A T-1/2 = 16(2) ns isomeric level. populated in the spontaneous fission of 248 Cm, has been found in Zr-101 at 941.8 keV in a measurement of prompt gamma-rays using the EUROGAM2 array. The level is interpreted as a K-isomer corresponding to the 9/2[404] neutron-hole excitation. The quadrupole moment, Q(o) = 3.6(4) eb, deduced for the new band indicates a large deformation Of beta(2) = 0.38(4), which is produced by a specific shape-coexistence mechanism. This is another observation of the nu9/2[404] orbital in the mass A similar to 100 region, confirming the presence of the effect reported first in our previous work. The 9/2[404] neutron-hole excitation is also confirmed in the Sr-97 nucleus and the deformation beta(2) = 0.44(2) is determined for this configuration. The properties of the 9/2[404] neutron orbital and its influence on the onset of deformation in the A similar to 100 region are discussed.