No abstract

Recent antisymmetrized molecular dynamics (AMD) calculations for28 Si suggest the presence of a superdeformed (SD) band with a dominant 24 Mg+α clustering for its configuration, with firm predictions for its location and associated moment of inertia. This motivates a review of the experimental results reported in the literature with a particular focus on 24 Mg(α,γ) studies, as well as on alpha-like heavy-ion transfer reactions such as 12 C( 20 Ne,α) 28 Si. Combining this information for the first time, leads to a set of candidate SD states whose properties point to their alpha-cluster structure and strong associated deformation. Analysis of data from Gammasphere allows the electromagnetic decay of these candidate states to be probed and reveals further supporting evidence for such a structure. This paper appraises this body of information and finds the evidence for an SD band is strong.

The half-life of the 6 + state in 174 Yb of 830(50) µs was incorrectly shown as the mean-life on the level scheme (Fig. 2) and in Table III where transition strengths were listed. Use of the corresponding mean-life of 1198(72) µs and more accurate values for the intensity of the 1265 keV and 628 keV branches leads to the modified transition strengths and hindrances given below, where the main part of the table is reproduced. (Errors are also shown on the reduced hindrances for the 628 and 1265 keV transitions.) The modifications do not affect the original conclusions. Several other typographical errors are corrected in the table, including the unit for magnetic transitions which had been omitted and a degree of forbiddenness of ν = 3 rather than ν = 4 for the 193 keV E2 transition from the 7 − isomer. Also, on p. 8 of the text, in reference to the tunneling estimate for the 6 + , E2 hindrance, the predicted value was given as F = 7.5 × 10 8 . This should have read F = 7.5 × 10 7 which corresponds to the reduced hindrance value f ν = 93 quoted in the text and used in the interpretation.