E2 moments of the Sc43(19/2-) and the Ti43(19/2-) states and the Ca40 core deformation

Quadrupole coupling constants of the Sc43(19/2-) and the Ti43(19/2-) mirror isomers, implanted into hexagonal Ti, have been measured with the time differential perturbed angular distribution method. Values of e2qQh=8.5(19) MHz and 8.0(16) MHz are found at room temperature, corresponding to eQ=19.9(14) efm2 and 30(7) efm2 for the Sc43(19/2-) and the Ti43(19/2-) states, respectively. The isomeric lifetimes were remeasured as T12=469(4) nsec and 553(21) nsec for the two states. These values, along with transition rates of high spin states in A=42 nuclei were analyzed in terms of effective charges, and were found to be consistent with en=0.56(7) and ep=1.26(9) for the quadrupole moments, en=0.65(3) and ep=1.35(5) for the B(E2) values. The slight increase in the effective charges for the nondiagonal compared to the diagonal E2 matrix elements is understood as the effect of an increased core deformation in the lower spin partner of the transition. NUCLEAR REACTIONS Al27[F19,p 2n] Sc43(192-), E(F19)=45.5 MeV; Ca40[±,p] Sc43(192-), Ca40[±,n] Ti43(192-), E±=21 MeV; pulsed beam, measured T12, deduced B(E2), measured (,,t) in Ti metal, deduced Q.