Electronic structure theory of the superheavy elements

Laser spectroscopy studies on nobelium

“…The atomic and chemical properties of the heaviest elements (Z 100) are affected by strong relativistic effects and quantum electrodynamics [1][2][3]. Relativistic effects increase approximately with the square of the atomic number and are responsible for the distinct color of gold and for the liquid state of mercury at room temperature.…”

Heaviest Element Has Unusual Shell Structure

“…For example, the relativistic 7p 3=2 expansion and the relativistic 8s contraction make Og the first rare gas element with a positive electron affinity of 0.064 eV [10,16,22]. This result includes a substantial quantum electrodynamic correction of 0.006 eV [16].Nuclear structure calculations predict 294 Og to be a deformed nucleus [23][24][25][26], eight neutrons away from the next neutron shell closure at 302 Og (N ¼ 184) [27][28][29][30][31][32]. A new factor impacting properties of superheavy nuclei is the strong electrostatic repulsion: The Coulomb force in superheavy nuclei cannot be treated as a small perturbation atop the dominating nuclear interaction; the resulting polarization effects due to Coulomb frustration are expected to influence significantly the proton and neutron…”

“…This effect, particularly strong for neutrons, is due to the high density of single-particle orbitals. 118 Og, 0.89 þ1.07 −0.31 ms, is too short for chemical "oneatom-at-a-time" studies; hence, its chemical properties must be inferred from advanced atomic calculations based on relativistic quantum theory [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. According to these, Og has a closed-shell ½Rn 5f 14 6d 10 7s 2 7p 6 configuration [13,20,21], with a very large spin-orbit splitting of the 7p shell (9.920 eV at the Dirac-Breit-Hartree-Fock and 10.125 eV at the Fock-space coupled-cluster level; see below).…”

“…In contrast to its electronic configuration (Og completes the seventh period of the periodic table), it is not expected to behave like a typical rare gas of group 18. For example, the relativistic 7p 3=2 expansion and the relativistic 8s contraction make Og the first rare gas element with a positive electron affinity of 0.064 eV [10,16,22]. This result includes a substantial quantum electrodynamic correction of 0.006 eV [16].…”

“…Here we used the molecular meanfield X2C Hamiltonian [56] with the Gaunt term included. Fock-space coupled-cluster calculations [16] were carried out to obtain the ionization potentials from the filled 7p 3=2 and 7p 1=2 shells of Og. Note that only large-component densities are considered for the nonrelativistic and scalarrelativistic ELF, whereas in the four-component case the small-component densities are added to the large components to yield the total one-particle density.…”