Fission barriers of actinide nuclei with nuclear density functional theory: influence of the triaxial deformation

The fission pathway of even–even actinide nuclei have been systematically calculated using the deformation-constrained nuclear density functional theory beyond the second fission barriers within the UNEDF1 energy-density functionals (EDFs). Our calculated results show that, allowing for triaxial deformation, the second fission barriers are lowered by a few hundreds of keV to 2 MeV. For the heaviest actinides, it is found that inclusion of triaxial deformation reduces the outer barrier significantly.