Structure of 60,62Fe and the onset of νg9/2 occupancy

Level structures in 60,62 Fe 34,36 and adjacent nuclei were studied with Gammasphere using the reaction of a 430-MeV 64 Ni beam on a 55-mg/cm 2 thick 238 U target. High-spin level schemes were deduced from singly-and doubly-gated prompt coincidence events. Levels populated in the β decay of 60,62 Mn isomers were studied in singly- and doubly-gated delayed coincidences. Spin and parity assignments were deduced from angular correlations of γ rays observed in both nuclei, leading to firm positive-parity yrast assignments up through 8 + in 62 Fe. The observed levels for 60 Fe up to ~3.5 MeV compare well with pf shell-model calculations available in the literature. Calculations performed in a limited pfg basis exhibit reasonable agreement for the 2 + ,4 + , and 6 + levels in 62 Fe, However, theoretical descriptions that include the newly identified negative-parity levels in 62 Fe require a much larger basis, necessarily including g 9/2 neutrons, as well as improved interactions leading to negative-parity levels.