Collective and noncollective excitations in odd-evenN=83nuclei

Abstract

We have studied the level structure of the even-odd $N=83\mathrm{}$ nuclei ${}_{60}{}^{143}{}_{}{}^{}\mathrm{Nd}$, ${}_{62}{}^{145}{}_{}{}^{}\mathrm{Sm}$, ${}_{64}{}^{147}{}_{}{}^{}\mathrm{Gd}$, and ${}_{66}{}^{149}{}_{}{}^{}\mathrm{Dy}$. In order to explain the high level density above 2 MeV and low-lying high-spin states ($J>\mathrm{}\frac{13}{2}$;$E_x>2.5\mathrm{}$ MeV), a Hamiltonian is constructed which in addition to the collective vibrations of the core, describes also the two quasiparticle excitations of the protons in the $Z=50-82\mathrm{}$ shell. The results of the calculations are compared with the experimental data concerning the $N=83\mathrm{}$ nuclei.