Intermediate particle-core coupling in reflection asymmetric odd mass nuclei

Abstract A coupling scheme between a collective core, with quadrupole and octupole deformation, and a single-particle spin is proposed to describe the complex distribution of the negative and positive parity states in odd mass nuclei. The model is based on an axially symmetric quadrupole-octupole geometric Hamiltonian with an adjustable particle-core coupling, offering a wide range of spectroscopic structures. A specific instance of the model, involving a moderate coupling strength, is identified in $$^{151}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>151</mml:mn> </mml:mmultiscripts> </mml:math> Ce, $$^{153}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>153</mml:mn> </mml:mmultiscripts> </mml:math> Nd, $$^{223}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>223</mml:mn> </mml:mmultiscripts> </mml:math> Ra and $$^{225}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>225</mml:mn> </mml:mmultiscripts> </mml:math> Th nuclei, respectively discussed in terms of energy levels and relevant electric transitions.