The nuclear spin-spin coupling in N₂ and CO

Molecules with multiple bonds are challenging for computations of nuclear spin-spin coupling constants. This can be referred to the asserted importance of non-contact mechanisms, to sharp geometry variations as well as to the handling of the electronic structure problem. We employ a recently developed multi-configuration linear response theory for calculations of nuclear spin-spin coupling constants in molecular nitrogen and carbon monoxide and explore systematically the role of correlation for the Fermi contact as well as the other main non-contact mechanisms.