Soft triaxial roto-vibrational motion in the vicinity of $\gamma =\pi /6$

Abstract

A solution of the Bohr collective hamiltonian for the $\beta -$soft, $\gamma -$soft triaxial rotor with $\gamma \sim \pi /6$ is presented making use of a harmonic potential in $\gamma$ and Coulomb-like and Kratzer-like potentials in $\beta$. It is shown that, while the $\gamma -$angular part in the present case gives rise to a straightforward extension of the rigid triaxial rotor energy in which an additive harmonic term appears, the inclusion of the $\beta$ part results instead in a non-trivial expression for the spectrum. The negative anharmonicities of the energy levels with respect to a simple rigid model are in qualitative agreement with general trends in the experimental data.

4 pages, 2 figures, accepted in Phys.Rev.C