Level Structure of ¹⁷⁷Lu Studied through the Beta Decay of ¹⁷⁷Yb

Abstract

The level scheme of ¹⁷⁷Lu following the β-decay of ¹⁷⁷Yb (T_1/2=1.9, h) has been constructed from results of γ singles and γ-γ coincidence measurements. Angular correlations of γ-rays were measured with a 4-Ge detector system. Mixing ratios (E2/M1) of seven γ-rays were obtained. The spins and parities of the 1049.4, 1150.0 and 1241.7, keV levels have been assigned to be 9/2^-, 7/2⁺ and 7/2⁺, respectively. These assignments for the 1049.4 and 1241.7, keV levels are consistent with the interpretation that these levels are members of three-quasiparticle multiplets. Energy splittings of three-quasiparticle states were calculated. The calculated 1160, keV 7/2⁺ level may correspond to the observed 1150.0, keV 7/2⁺ level. A calculation with a rotation-vibration coupling model was performed. The K-2 γ-vibrational state of the 7/2⁺[404] state and the K± 2 γ-vibrational states of the 9/2^-[514] state are expected to exist near 1300, keV.