High-spin states of the semimagic nucleusPr141

Abstract

High-spin states of the semimagic nucleus $^{141}\mathrm{Pr}$ have been investigated by in-beam $\ensuremath{\gamma}$-spectroscopic techniques using the fusion-evaporation $^{138}\mathrm{Ba}(^{7}\mathrm{Li},\phantom{\rule{0.16em}{0ex}}4n)$ reaction at a beam energy of 38 MeV. The level scheme of $^{141}\mathrm{Pr}$ has been extended up to $\ensuremath{\sim}6.2$ MeV in excitation energy and $35/2 \ensuremath{\hbar}$ in spin. A total of 14 new levels and 30 new transitions have been assigned to $^{141}\mathrm{Pr}$ on the basis of $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ coincidence information. The observed level structures are discussed in light of the available experimental data and shell model calculations with the oxbash code. According to the calculations, most of the observed levels of $^{141}\mathrm{Pr}$ are from the proton excitations above the $Z=50$ shell. Possible evidence for the neutron excitations across the $N=82$ gap in $^{141}\mathrm{Pr}$ is also discussed and compared with other $N=82$ isotones.