Effects of configuration mixing on predominantlyf 7 2/n states inA=52?55 nuclei

Abstract

Extensive shell-model calculations are performed on f3/2 nuclei with A=52-55. The model space includes the excitation of one fT/z nucleon to the P3/2, f5/2 or Pl/2 orbit. Spectra, electromagnetic properties (M1, E2, E4) and /~-decay are studied. It is found that almost all observables calculated in the enlarged space are in much better agreement with experiment than those of the simple f~/z space.

Effects beyond first-order perturbation theory in the polarization charges forE4 transitions

“…The theory would suggest that isoscalar effective charges of order 4 and 6 would follow the trend of lower multipoles and be associated with an enhancement of isoscalar electric transitions. This is however not the case for several E4 (and E6) transitions in the f-p shell which exhibit significantly retarded transition rates compared with shell model estimates [3,4,5]. We then examine whether core polarization could be invoked to explain these anomalous E4 transitions and conclude that effects beyond core polarization or first order perturbation theory are required to explain the data.…”