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The half-life of a Kπ = 12+ isomer in 164Er has been measured to be 68(2) ns, and new decay pathways have been identified. These include highly K-forbidden y-ray transitions directly to the ground-state rotational band, with reduced hindrance values that can be compared with those found for heavier nuclides. The new data support the interpretation that the level density is a key variable in determining K-forbidden transition rates. [ABSTRACT FROM AUTHOR]

High-spin states in the 16468Er96 region were studied using 9Be + l60Gd reactions. Pulsed beam conditions were exploited for enhanced sensitivity to delayed &ggr;-ray transitions. New isomers were identified in 16lDy, l63Ho, 162Er, and l65Er. The l62Er isomer is interpreted to decay by E1 transitions to the ground-state band with a reduced hindrance of fv = 33. A plot of fv values for all &Dgr;K = 7, E1 transitions from two-quasiparticle isomers to the ground-state bands of even-even nuclei reveals only a small influence from the dynamic to kinematic moment-of-inertia ratio, which provides a measure of Coriolis K mixing within the ground-state band. This is interpreted to imply that the relatively low hindrances are due to K mixing in the isomer, caused by a combination of Coriolis and octupole band mixing. [ABSTRACT FROM AUTHOR]

The 160Gd(9Be,α3n)162Dy reaction has been used to study high-spin states in 162Dy. Pulsed beam conditions were utilized for enhanced isomer sensitivity. An isomer at 2188.1(3) keV with a half-life of 8.3(3) μs has been discovered and assigned Kπ= 8+ with a two-quasineutron configuration. Among 11 γ-ray decay branches, an E2, ΔK=8 transition to the ground-state band was observed with a reduced hindrance of ƒv=35, agreeing well with systematics correlating ƒv with the product of the valence neutron and proton numbers (NpNn) over an extended N,Z range. Small deviations from NpNn dependence are analyzed for a range of two-quasiparticle isomer decays and interpreted as arising from a weak dependence on the isomer excitation energy relative to the yrast line. [ABSTRACT FROM AUTHOR]