Probing high-order deformation effects in neutron-deficient nuclei $^{246,248}$No with improved potential-energy-surface calculations

The high-order deformation effects in even-even $^{246,248}$No are investigated by means of pairing self-consistent Woods-Saxon-Strutinsky calculations using the potential-energy-surface (PES) approach in an extended deformation space $(\beta_2, \beta_3,\beta_4,\beta_5,\beta_6,\beta_7, \beta_8)$. Based on the calculated two-dimensional-projected energy maps and different potential-energy curves, we find that the highly even-order deformations have an important impact on both the fission trajectory and energy minima, while the odd-order deformations, accompanying the even-order ones, primarily affect the fission path beyond the second barrier. Relative to the light actinide nuclei, nuclear ground state changes to the superdeformed configuration but the normally-deformed minimum, as the low-energy shape isomer, may still be primarily responsible for enhancing nuclear stability and ensuring experimental accessibility in $^{246,248}$No. Our present investigation indicates the nonnegligible impact of high-order deformation effects along the fission valley and will be helpful for deepening the understandings of different deformation effects and deformation couplings in nuclei, especially in this neutron-deficient heavy-mass region.