Nuclear spin-spin coupling constants from regular approximate relativistic density functional calculations. I. Formalism and scalar relativistic results for heavy metal compounds

A simple, transparent and computationally efficient method to obtain nuclear spin-spin coupling constants from scalar zeroth-order regular approximation (ZORA) relativistic density functional computations with the ADF program is presented. The key feature of this method is the fast solution of the first-order coupled perturbed Kohn-Sham equations corresponding to the Fermi-contact-type perturbation operator.