Microscopic analysis of octupole shape phase transitions and critical points in neutron rich actinides

Abstract

Octupole constrained energy surfaces, and spectroscopic observables of four isotopic chains of: Cm, Cf, Fm and No with neutron numbers 186 N200 are analysed using a collective quadrupole - octupole Hamiltonian (QOCH). The parameters of the Hamiltonian are determined by axially reflection-asymmetric relativistic Hartree-Bogoliubov calculations based on the energy density functional DD-PC1, and a finite-range pairing interaction. The theoretical results suggest quantum phase transitions from non-octupole to octupole deformed shapes and to octupole vibrations with increasing neutron number.  288Cm is possibly close to the critical point of a simultaneous  phase transition from spherical to prolate deformed and from non-octupole to stable octupole deformed configurations.