Triaxial Shape, Signature Splitting, and Shape Coexistence in 127,129,131Nd

Signature splitting and shape coexistence at high spin in the neutron deficient nucleus 129Nd are investigated with the configuration-dependent cranked Nilsson–Strutinsky approach. The calculated bands are compared with the observed signature partner bands and very good agreement results at high spin are obtained. The observed deformed bands are confirmed as normal and highly deformed and their properties are explained theoretically. Terminating states in 129Nd and other terminations are predicted. There is shape coexistence within the same configuration from low-spin states to high-spin states. Possible normal and highly deformed bands with rotation around the intermediate principal axis in several interesting configurations of 129Nd are discussed. The experimental results for 131Nd are simply discussed and the calculated bands are in good agreement with observed bands at high spin. Triaxial shapes in 127Nd with a triaxial deformation of γ ~ −12° are predicted and should be observed experimentally. The value of negative γ of π(h11/2)4v(h11/2)7 configuration increases with neutron number increasing in 127,129,131Nd. The triaxial shape evolutions with neutron number increasing in 127,129,131Nd and in 126,128,130,132Pr are explained by the strong driving force of specified single particle orbitals towards to triaxial shape.