A study of positive-parity states in 15O
1968; Elsevier BV; Volume: 106; Issue: 3 Linguagem: Inglês
10.1016/0375-9474(68)90523-x
ISSN1873-1554
AutoresRichard D. Gill, J.S. Lopes, B.C. Robertson, R.A.I. Bell, H. J. Rose,
Tópico(s)Astro and Planetary Science
ResumoA particle gamma coincidence technique was used to study the positive-parity levels of 15O located at 5.24 MeV (Jπ = 52+), 6.79 MeV and 6.86 MeV. The spins of the 6.79 MeV and 6.86 MeV levels were shown to be 32 and 52, respectively, and the multipole mixing ratios of the de-excitation gamma rays were determined with the following results: δ(5.24 → 0) = + 0.13±0.05, and E3/M2 mixture; δ(6.86 → 5.24) = −0.04±0.03, and E2/M1 mixture and δ(6.79 → 0) =−0.10±0.02 or 2.2±0.4, an M2/E1 mixture. The last mixing ratio indicates an exceptionally high retardation of an E1 transition in a non self-conjugate nucleus; a similar E1 retardation has been previously found in the mirror 15N transition. A comparison of the E3/M2, 5 MeV transition mixing ratios in 15O and 15N strongly suggests a collective character for the E3 components of these transitions. The results obtained, together with the corresponding results in 15N, are compared with the recent theoretical work of Shukla and Brown.
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