A study of levels in 25 Mg via the 22Ne (α,nγ)25Mg reaction

Levels in the nucleus 25 Mg have been studied by measurement of the angular distributions and polarization of gamma rays from the 22 Ne(α, nγ) 25 Mg reaction. Information regarding spins, parities, mixing ratios, and branching ratios has been obtained for the levels between 2.7 and 4.7 MeV excitation. Spin and parity assignments of 5/2 + and 7/2 − have been made to the levels at 3.90 and 3.97 MeV. Mixing ratios have been determined or restricted for most of the observed transitions. The decay branch of the 3.40 MeV level to the ground state is found to be considerably stronger than previously reported, bringing the decay properties of this level into good agreement with the predictions of the simple rotational model. The significance of the results within the framework of the rotational model is discussed. There is evidence for considerable band mixing in levels belonging to the second K π = 1/2 + and the K π = 1/2 − bands.