Nuclear stiffness evolutions against axial and non-axial quadrupole deformations in even-A osmium isotopes

Abstract

Systematic potential energy surface calculations for the ground states of even-even 162-200Os isotopes have been performed in (β2, γ, β4) deformation space. The shape instabilities are evaluated by analyzing the potential energy curves with respect to β2 and γ deformation degrees of freedom. Moreover, based on a simple harmonic approximation, the nuclear stiffnesses against β2 and γ deformations are quantitatively investigated. The present results are compared with previous calculations and available experiments. In addition, inspired by a recent study [N. Wang et al., Phys. Lett. B 734, 215 (2014)], we, taking the near-drip-line nucleus 162Os as an example, investigate the effects of potential parameter modifications (e.g., the strength of the spin-orbit potential, λ, and the nuclear surface diffuseness, a) on the deformation energy curve, showing the possible onset of a relatively low fission barrier (if a similar phenomenon occurs in a heavy or superheavy nucleus, the survival probability will be strongly affected).