The 7/2− Doublet in 55Fe

Abstract

An investigation of the Jπ = 7/2− states at 1316 and 1408 keV excitation in 55Fe is presented as a test of the coexistence of particle and hole states in that nucleus. The lifetimes were measured using the solid stopper Doppler shift attenuation technique, yielding values of [Formula: see text] and τ > 4 ps for the 1316 and 1408 keV levels respectively. The 1408 → 1316 keV branch was determined to be 2.5 ± 0.5%. The results are compared with other available experimental information and with the predictions of a quasiparticle–core coupling calculation. The model analysis indicates very limited mixing of particle and hole configurations.