Data from complementary experiments on the members of the ($3^{\mathrm{-}}$ν$f_{7/2}$) multiplets in ${}_{{}_{60}{}^{143}{}_{}{}^{}}{}^{}{}_{}{}^{}\mathrm{Nd}_{83}^{}{}_{}{}^{}$, ${}_{{}_{62}{}^{145}{}_{}{}^{}}{}^{}{}_{}{}^{}\mathrm{Sm}_{83}^{}{}_{}{}^{}$, and ${}_{{}_{64}{}^{147}{}_{}{}^{}}{}^{}{}_{}{}^{}\mathrm{Gd}_{83}^{}{}_{}{}^{}$ are summarized and the particle-vibration coupling is investigated. It is shown that for odd N=83 nuclei the quadrupole-quadrupole interaction gives the leading contribution in the energy displacements of the multiplet members and that it can essentially explain the spin order and the absolute values for the splitting of the observed particle-octupole multiplets.

• Received 16 December 1988

DOI:https://doi.org/10.1103/PhysRevC.40.1006