Predictions of stable Yb - in the P o 1/2 state: the importance of spin-orbit coupling

Density functional theory calculations on Yb - using the Hartree-Fock system and the analogous Dirac-Hartree-Fock methods predict that Yb - is stable in the P o 1/2 state. The electron affinity obtained after the correlation energy functionals used are calibrated against Ca - and Lu is 21 mHartree (4327 meV). The calculations indicate that the P o 3/2 state is unlikely to be bound due to spin-orbit coupling reducing its binding energy.