Relativistically corrected electric field gradients calculated with the normalized elimination of the small component formalism

Abstract

Based on the analytic derivatives formalism for the spin-free normalized elimination of the small component method, a new computational scheme for the calculation of the electric field gradient at the atomic nuclei was developed and presented. The new computational scheme was tested by the calculation of the electric field gradient at the mercury nucleus in a series of Hg-containing inorganic and organometallic compounds. The benchmark calculations demonstrate that the new formalism is capable of reproducing experimental and theoretical reference data with high accuracy. The method developed can be routinely applied to the calculation of large and very large molecules and holds considerable promise for the interpretation of the experimental data of biologically relevant compounds containing heavy elements.

Relativistic calculations of magnetic resonance parameters: background and some recent developments

“…b Seventh-order SF DKH with PC corrections (DKH (7,7)) and DC (4c) with SO coupling and finite-nucleus model [81]. c SF NESC data [169]. d X2C with SO coupling.…”

“…Representative EFG data for the HX series are listed in table 1 along with SF 4c data, EFGs that are correct to order c −2 , and NR results that were reported in the same paper. EFGs have also been calculated within a scalar NESC framework [169] for X in the HX series and for Hg in 11 complexes with mercury, along with Hg contact densities for the latter. Excellent agreement between SF four-component, DKH7, X2C and NESC calculations is demonstrated for the popular HX benchmark set, as seen from the results provided in table 1.…”

Communication: On the isotope anomaly of nuclear quadrupole coupling in molecules

“…The electric field gradients at the gold nucleus are calculated utilizing a recently developed Dirac-exact relativistic methodology, 12 which is based on the normalized elimination of the small component (NESC) method 20,21 and on the analytic derivatives formalism for NESC. 22,23 The EFG is calculated as a derivative of the total electronic energy with respect to the NQM, where the NQI Hamiltonian is explicitly included when calculating the energy.…”

“…22,23 The EFG is calculated as a derivative of the total electronic energy with respect to the NQM, where the NQI Hamiltonian is explicitly included when calculating the energy. 12 When calculating the electronic energy and the NQI operator, the finite size nuclear model with the charge distribution described by a Gaussian function is employed. In the calculations carried out for AuF, AuCl, AuBr, AuI, XeAuF, KrAuF, ArAuF, and (CO)AuF molecules, the segmented all-electron relativistically contracted (SARC) basis set 24 modified as in Ref.…”

“…5,11 In this Communication, we investigate theoretically whether the quadrupole anomaly can be observed by experimental measurement of molecular NQCCs, where we base our study on the recently developed formalism for the calculation of the relativistically corrected electric field gradient at the nuclear site. 12 For the following reasons, the theoretical investigation is carried out for gold isotopes: (i) Gold (stable isotope 197 79 Au (I = 3/2)) has a number of long living neutron deficient isotopes, e.g., 195 79 Au (I = 3/2, τ 1/2 = 183 d), as well as neutron rich isotopes, e.g., 199 79 Au (I = 3/2, τ 1/2 = 3.14 d), with non-zero nuclear electric quadrupole moments. 13 (ii) Gold forms diatomic and triatomic molecules with halogens and rare gas atoms, for which NQCCs can be conveniently measured in the gas phase.…”