Structure of the highly deformed nucleus101Sr63 and evidence for identical K=3/2 bands

Abstract

Abstract. The low-energy level scheme of the N = 63 nucleus 101Sr has been obtained from a/3-decay study of l~ The u[53215/2 and u[41113/2 orbitals are well established as the ground state and a band head at 271.2keV, respectively. The general properties of the level scheme indicate a quadrupole deformation of/3 _~ 0.4, confirming the unique feature of saturation of deformation in N > 60 Sr isotopes. The energies of the K = 3/2 intraband transitions in the odd-neutron neighbours 99Sr61 and 1ol 8r63 are very similar. More generally, the identical bands at low spin in 98-1~ nuclei are correlated with the mass-independent moments of inertia in this region.

Shape coexistence in the odd-odd neutron-rich nucleusY98studied in the interacting boson model

“…The [541]3/2 orbital is associated with the levels at 644 keV and 614 keV Zr͑1039 keV͒ [15] and shortly later in 97 Sr͑830 keV͒ [16]. The next orbitals above the Fermi surface are [411]3/2 and [532]5/2 assigned to the ground states of N = 61 and N =63 isotones of Sr, Zr, and Mo [22][23][24][25][26].…”

Nuclear deformation in the A≈100 region: Comparison between new masses and mean-field predictions

“…Several β-decay studies have provided the identification of the lowest levels of rotational bands. These observations concerned mostly the even-even nuclei [9][10][11][12][13][14]. The drop of the energy of the first 2 + excited state at N = 60 in the strontium (Z = 38), zirconium (Z = 40), and molybdenum (Z = 42) isotopic chains was also regarded as a clear indication of their deformation [15].…”

The ν9/2[404] orbital and the deformation in the A ∼ 100 region

“…This level decays to the 7/2 + level at 308.1 keV via the 522.7 keV transition, analogous to the 786.8 keV transition from the (9/2 404]), 1038.8 keV isomer in 99 Zr. Assuming that the 522.7 keV transition has the same character as that of the 786.8 keV transition, and rescaling the partial half-life for the 786.8 keV decay, T 1=2 (768.8)= 186 (35) ns, with the factor (786.8/522.7) 3 (we neglect an E2 contribution) one obtains the expected partial half-life for the 522.7 keV decay of T ex 1=2 (522.7)=635(120) ns. This estimate is less than two standard deviations from the observed half-life of the 830.8 keV isomer in 97 Sr, for which only the 522.7 keV decay branch is known.…”