Quite general arguments indicate that if the shell-model picture holds or even if one allows for effective charge corrections, then the quadrupole moment of the first excited state of 48Ti should be small, and the magnetic moment of the first excited state of 54Fe should be large, compared to the rotational value. These results are contrary to recent experiments. A comparison is made between perturbation theory and matrix diagonalization in the space two holes and three holes and one particle, for 54Fe and 54Co. One gets less magnetic quenching with matrix diagonalization in54Fe (hence the deviation from experiment is more) than with perturbation theory. The possibility that the lowest 21 + state in 54Fe is mostly a 3p-1h state is ruled out. Corrections to the quasiparticle approximation i.e. the use of the magnetic moment of one hole (55Co) to calculate the magnetic moment two holes (54Fe), are calculated, and again tends to reduce the quenching. The J = 7 J = 0 splitting of two holes - 54Co - is less than that of two particles - 42Sc - by 400 keV but in perturbation theory the admixture of 3h-1p in 54Co goes in the wrong direction by 600 keV. It is shown however that with matrix diagonalization the J = 0 state of 54Co gets pushed down much less than in perturbation theory, so that this 600 keV additional discrepancy is erased. A triplet of levels at 2.5 MeV in 54Fe is analyzed to consist of a (mostly) 2h J = 4 state, a 3h-1p particle J = 2 state, and 4h-2p J = 0 state. A bare realistic interaction puts the 4h-2p state much too high in energy but an interaction chosen to fit single-particle energy shifts gives excellent agreement.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics