Neutron single-hole states in 149Sm, 157Gd and 196Au investigated by (p, d) reactions

In order to continue studies of neutron single-hole states in nuclei of 50 ≦ N ≦ 126, (p, d) reactions on 150Sm, 158Gd and 197Au have been investigated by the use of a proton beam of 55 MeV. Emitted particles were analysed with a broad-range magnetic spectrometer and detected with a 200 proportional counter system. Angular distributions of 39 deuteron groups are analysed with the aid of the DWBA method. The l-values are assigned, and Jπ values and the spectroscopic factor for each state are obtained. Many new excited states have been found and their Jπ values are given. Energy shifts of the neutron single-hole states of 3p12., 2f52, 3p32, li132, 2f72 and 1h92 observed between 207,205Pb and 196Au are interpreted on the basis of effective proton-neutron interactions. The observed energy shifts are reproduced rather well by the use of the interaction Vpn = (V0 + V1σp · σn)δ(rp − rn) and of the harmonic-oscil except for the case of the p12 state. In order to explain the shift of the p12 state relative to the p32 state, it is necessary to introduce some spin-dependent interactions such as tensor interactions and/or two-body spin-orbit interactions.