Configuration mixing of mean-field wave functions projected on angular momentum and particle number: Application to Mg-24

We present in this paper the general framework of a method which permits to restore the rotational and particle number symmetries of wave functions ob tained in Skyrme HF + BCS calculations. This restoration is nothing but a p rojection of mean-field intrinsic wave functions onto good particle number and good angular momentum. The method allows us also to mix projected wave functions. Such a configuration mixing is discussed for sets of HF + BCS in trinsic states generated in constrained calculations with suitable collecti ve variables. This procedure gives collective states which are eigenstates of the particle number and the angular momentum operators and between which transition probabilities are calculated. An application to Mg-24 is presen ted, with mean-field wave functions generated by axial quadrupole constrain ts. Theoretical spectra and transition probabilities are compared to the ex periment. (C) 2000 Elsevier Science B.V. All rights reserved.