Springer Online Journal Archives 1860-2000
Abstract Spin assignments have been made to the25Mg levels in theE x=5–6 MeV region fromγ-ray angular distributions measured in the22Ne(α, n y) reaction atE α=8.0 and 8.8 MeV and fromp-γ angular correlations measured in the24Mg(d, p γ) reaction atE d=6 MeV. Unique spin assignments ofJ=7/2, 5/2, 5/2, and 9/2 could be made to the levels atE x=5005, 5511, 5851, and 5967 keV, respectively. Ambigious assignments have been made to the levels atE x=5245, 5524, 5785, 6032 keV (J=11/2, 7/2), 5455 keVJ=13/2, 9/2), and 5738 keV (J=3/2, 5/2). The present data confirm previous assignments ofJ=1/2 to the levels atE x=5108 and 5466 keV, respectively. Lifetime estimates have been obtained, using the Doppler-shift attenuation method, for the levels atE x=5245 keV (τ=30–60 fs), 5785 keV (τ=50–100 fs), 5967 keV (τ=50–100 fs), and 5455 keV (τ〉1ps). All other levels in theE x=5–6 MeV region haveτ〈60 fs. A breakdown of theK-selection rule has been observed in theγ-decay of some high spin states, indicating a deviation from the strong coupling model.
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