Nuclear spin–spin coupling constants from regular approximate relativistic density functional calculations. II. Spin–orbit coupling effects and anisotropies

Based on our recently published two-component relativistic formulation of the nuclear spin–spin coupling hyperfine terms, we present a full implementation into the Amsterdam Density Functional program. The scalar relativistic code has been extended to include the relativistic analogue of the spin–dipole operator in the coupling calculations, which can now in addition be based on two-component spin–orbit coupled Kohn–Sham orbitals. One-bond coupling constants for some plumbanes are in good agreement with experiment, slightly improving the scalar relativistic values. Coupling constants and anisotropies for the XF (X=Cl, Br, I) and TlX (X=F, Cl, Br, I) series are compared to experimental data and for ClF additionally to recently published ab initio calculations. The spin–dipole term contributes largely to the coupling constants in XF. Spin–orbit effects are essential for the TlX couplings, where they can yield the most important contributions. In addition, data is reported for the benchmark systems ethane, ethene, and ethyne.