Ground-state phase transition in odd-Aand odd-odd nuclei nearN=90

Abstract

Ground-state phase transitions in odd nuclei are examined. Especially, the phase transitions in odd-odd nuclei are revealed. It is found that odd-even effects may reach their maximal or minimal values around the critical point at $N=90$; the signals of phase transition in odd nuclei are greatly enhanced relative to those in the adjacent even-even species. Moreover, a pairing model analysis of the phase transition in Sm isotopes indicates that the critical behaviors related to pairing may be driven by the decrease in the pair strength $G$ with a sudden flattening in $\ensuremath{\Delta}G$ around the critical point.