About the calculation of exchange coupling constants using density-functional theory: The role of the self-interaction error

TLDR

The study evaluated exchange coupling constants in transition‑metal complexes using recent meta‑GGA and hybrid functionals, and examined how basis set choice and pseudopotentials affect J values in a Fe(III) dinuclear complex with multiple unpaired electrons. Correcting the self‑interaction error removes spurious nondynamical correlation contributions in DFT calculations, improving the accuracy of exchange coupling constants.

Abstract

The effect of the correction of the self-interaction error on the calculation of exchange coupling constants with methods based on density-functional theory has been tested in simple model systems. The inclusion of the self-interaction correction cancels the nondynamical correlation energy contributions simulated by the commonly used functionals. Hence, such correction should be important in the accurate determination of exchange coupling constants. We have also tested several recent functionals to calculate exchange coupling constants in transition-metal complexes, such as meta-GGA functionals or new formulations of hybrid functionals. The influence of the basis set and of the use of pseudopotentials on the calculated J values has also been evaluated for a Fe(III) dinuclear complex in which the paramagnetic centers bear several unpaired electrons.