Angular momentum projected analysis of quadrupole collectivity in Mg-30,Mg-32,Mg-34 and Si-32,Si-34,Si-36,Si-38 With the Gogny interaction

A microscopic angular momentum projection after variation is used to descri be quadrupole collectivity in Mg-30,Mg-32,Mg-34 and Si-32,Si-34,Si-36,Si-38 . The Hartree-Fock-Bogoliubov states obtained in the quadrupole constrained mean field approach are taken as intrinsic states for the projection. Exci tation energies of the first 2(+) states and the B(E2,0(+)-->2(+)) transiti on probabilities are given. A reasonable agreement with available experimen tal data is obtained. It is also shown that the mean field picture of those nuclei is strongly modified by the projection. (C) 2000 Published by Elsev ier Science B.V. All rights reserved.