Excitation of the N = 28 Core in 53Mn

The structure of 53Mn is examined using a shell model basis of f7/2−2 and all f7/2−4j states, with an effective interaction derived from previous studies of fp shell nuclei. With few exceptions, the lowest one particle, four hole states are found to be predominantly neutron excitations, which make up over 99% of the lowest J = 13/2 level. The calculation successfully accounts for the observed high spin states, but comparison with experiment strongly suggests that two particle excitations from the f7/2 shell are the dominant configuration of several states lying below 3.5 MeV.