Relativistic coupled cluster calculations of the electron affinity and ionization potential of Nh(113)

Abstract

Theoretical calculations based on the Dirac--Coulomb--Breit relativistic coupled cluster method have been carried out for the electron affinities and ionization potentials of the superheavy element nihonium (Nh) and its lighter homologues In and Tl. The In and Tl calculations are in agreement with measurement within uncertainties. For Nh, where experiment is yet unknown, we predict the ionization potential of 7.569(48) eV and electron affinity of 0.776(30) eV.

Relativistic Coupled‐Cluster Calculations of Spectroscopic Properties of Copernicium and Flerovium Monoxides

“…This value is also used to estimate the unknown higher‐order relativistic and QED contributions. The previous studies of SHE suggest that this estimation is reasonable for various atomic properties including IP [32,34] …”

“…The previous studies of SHE suggest that this estimation is reasonable for various atomic properties including IP. [32,34] The difference between the values obtained within the CCSD and CCSD(T) approaches serves as an estimate of the contribution of the triple excitations. This estimation is in agreement with the deviation between three different schemes of taking into account the perturbative triple excitations: CCSD(T), CCSD + T, and CCSDÀ T. CCSD + T [47] includes fourthorder terms only, while CCSD(T) [48] also includes some part of the fifth-order terms, and CCSDÀ T [49] includes one more fifthorder term.…”

“…The FSCC implementation in the DIRAC package does not allow taking into account the triple excitations. To estimate its contributions to the molecular IP, we refer to heavy atom calculations, [32,34,54] where, in particular, for the flerovium and copernicium atoms the triple excitations contribute at the level of 0.2 %. For the molecules under consideration, we use a conservative 1 % estimate which is roughly 0.1 eV for the FlO molecule.…”

“…This approach is widely used in calculations of different properties of atoms and molecules and is considered to be reliable and accurate. [31][32][33][34] A challenging aspect of the theoretical investigations in this field is also the lack of a straightforward scheme for reliable uncertainty evaluation. However, an accuracy assessment is needed for reliable predictions of SHE properties and interpretation of rare experimental data.…”

“…We use the relativistic CCSD(T) method with the all‐electron Dirac–Coulomb (DC) Hamiltonian and its two‐component analogue (X2C). This approach is widely used in calculations of different properties of atoms and molecules and is considered to be reliable and accurate [31–34] …”