Shell-model calculations in A = 28-32 nuclei

Shell-model calculations for positive-parity levels of A = 28-32 nuclei have been performed in a 1d5/2 2s1/2 1d3/2 configuration space. Configuration mixing of at most 250 lowest-lying pure configurations for each (A, J, T) set was taken into account. By a variation of the four effective interaction (MSDI) parameters and three single-particle energies a search was made for the best fit of the calculated energies to the experimental values. The average deviation between theory and experiment for the energies of the 110 fitted levels is 0.44 MeV. By adjusting all the 63 two-body matrix elements (ASDI) and the tree single-particle energies, the average deviation of the binding energies was reduced to 0.16 MeV. For the lowest 10-15 levels in all A = 28-32 nuclei a one correspondence exists between theory and experiment. Electromagnetic transition strengths were calculated both with MSDI and with ASDI wave functions. The ASDI wave functions reproduce the experimental E2 data much better than the MSDI wave functions. For the M1 transition strengths only a minor improvement has been achieved. (orig.)