Spin-orbit effects approximately scale like Z(2) and therefore become very important in the bonding of the heavier p-group elements in the periodic table. Here we show by first-principles density-functional calculations that such effects substantially lower the cohesive energy for solid lead and Uuq (ununquadium, eka-lead, nuclear charge 114), by 2.5 eV/atom for the latter and causing a structural change from face-centered cubic at the scalar relativistic to hexagonal close packed at the spin-orbit coupled level of theory. This implies that unlike lead (cohesive energy E(coh) = 2.02 eV/atom), Uuq is weakly bound (E(coh) = 0.5 eV/atom), and even less so than solid mercury (E(coh)= 0.7 eV/atom), underpinning the original hypothesis by Pitzer in 1975 [K. Pitzer, J. Chem. Phys. 63, 1033 (1975)] that spin-orbit effects lead to chemical inertness of Uuq.
|Number of pages||8|
|Journal||Physical review B: Condensed matter and materials physics|
|Publication status||Published - 8 Oct 2010|
- GENERALIZED GRADIENT APPROXIMATION
- BRILLOUIN-ZONE INTEGRATIONS
- AUGMENTED-WAVE METHOD
- PSEUDOPOTENTIAL CALCULATIONS