High spin structure in odd-proton nuclei 129,131Pr.

Abstract

High spin states in $^{129}\mathrm{Pr}$ and $^{131}\mathrm{Pr}$ have been investigated using in-beam \ensuremath{\gamma}-ray spectroscopy techniques. The yrast band of $^{129}\mathrm{Pr}$ based on the ${\mathit{h}}_{11/2}$ 3/${2}^{\mathrm{\ensuremath{-}}}$[541] proton configuration was observed from 11/${2}^{\mathrm{\ensuremath{-}}}$ up to 43/${2}^{\mathrm{\ensuremath{-}}}$. The band based on the same configuration and two positive-parity side bands based on the ${\mathit{g}}_{7/2}$ 5/${2}^{+}$[413] proton configuration, were observed in $^{131}\mathrm{Pr}$. The delayed yrast band crossing of $^{129}\mathrm{Pr}$ at \ensuremath{\Elzxh}${\mathrm{\ensuremath{\omega}}}_{\mathit{c}}$=0.37 MeV is interpreted as being due to the alignment of the second and third ${\mathit{h}}_{11/2}^{\mathrm{\ensuremath{-}}}$ protons. The band crossing at \ensuremath{\Elzxh}${\mathrm{\ensuremath{\omega}}}_{\mathit{c}}$=0.26 MeV, with a gain in alignment of about 8\ensuremath{\Elzxh}, based on the ${\mathit{g}}_{7/2}$ 5/${2}^{+}$[413] configuration in $^{131}\mathrm{Pr}$ was attributed to the alignment of two ${\mathit{h}}_{11/2}$ protons. The systematics of the proton alignments in a series of Pr isotopes is discussed.