Microscopic Description of 2α Decay in ^212Po and ^224Ra Isotopes

A microscopic calculation of half-lives for both the α and 2α decays of ^212Po and ^224Ra is performed, using a self-consistent framework based on energy density functionals. A relativistic density functional and a separable pairing interaction of finite range are used to compute axially symmetric deformation energy surfaces as functions of quadrupole, octupole, and hexadecapole collective coordinates. Dynamical least-action paths are determined, that trace the α and 2α emission from the equilibrium deformation to the point of scission. The calculated half-lives for the α decay of ^212Po and ^224Ra are in good agreement with data. A new decay mode, the symmetric 2α emission, is predicted with half-lives of the order of those observed for cluster emission.