High-spin structure of 182,184Os in tilted axis cranking approach Original Research Article

A detailed investigation of the high-spin structures of 182,184Os has been carried out following a self-consistent two-dimensional (in the x-z plane) tilted axis cranked HFB approach employing a pairing-plus-quadrupole model interaction Hamiltonian. The tilt angle ψ is measured with respect to the x-axis so that ψ = 90° represents the nuclear symmetry z-axis. We have investigated the variation of the shape parameters for a given value of spin, J (up to J = 40) as a function of ψ. With the force parameters considered here, we do not find for any J the lowest energy solution corresponding to a tilted axis rotation. However, for spins in the region of the backbend (J ≈ 16) and beyond, the shape parameters change in a complex manner exhibiting local minima as a function of ψ. This implies the importance of the dynamical effects due to the wobbling motion of the rotation axis which warrants treatment through a dynamical theory like the generator coordinate method (GCM). Thus, unlike in the low-mass rare-earth region, here the cranking result cannot be directly compared with the experimental data, though for J ≳ 30 the J = K (ψ = 90°) states may turn out to remain the yrast, where K is the projection of J on the symmetry axis. We also find that the deformation aligned configurations for these two isotopes show important differences, particularly for K ≲ 20.