Absolute E1, ΔK = 1 transition probabilities between multi-quasiparticle high-spin states in 176Hf and 178Hf

Abstract

Applying the generalized centroid shift method in (α, 2n) reactions, the half-lives of the 3080 keV 15 + state in 176Hf and of the 1637 keV 5 − state in 178Hf have been measured as T 1 2 = 0.20 +0.12 −0.08 ns and T 1 2 = 0.40 ± 0.10 ns , respectively. B(El) values of K-allowed E1 transitions n 9 2 + [624]→ 7 2 − [514] are derived, and together with other data on similar transitions in odd- A nuclei, compared with predictions of the Nilsson plus pairing model. In 176Hf, the 15 + and 14 − states at 3080 and 2866 keV, respectively, appear as quite pure deformed 4QP configurations. In the 2QP state at 1637 keV in 178Hf, possible strong mixing of vibrational components is discussed coupled via 2QP K-admixtures arising from the partial alignment of the i 13 2 neutron.