Relativistic Effects on Magnetic Response

Nuclear Magnetic Resonance (NMR) is a powerful spectroscopic method for elucidating molecular structures, ranging from small molecules to complex biological macromolecules. Central to NMR is the relationship between the external magnetic field and the magnetically induced current density (MICD), which provides insights into molecular aromaticity and magnetic properties. While MICD information is challenging to obtain experimentally, theoretical calculations offer a robust alternative.
Relativistic effects, particularly spin-orbit-relativistic (SOR) interactions, play a critical role in the magnetic response of molecules containing heavy elements. These effects influence NMR shifts and MICD topologies but are computationally intensive to model, limiting their exploration. Recent advancements have highlighted the significance of SOR effects in heavy transition metal hydrides, revealing distortions in MICD and unusual shielding phenomena. However, a systematic study of SOR contributions to MICD remains unexplored.
The REMAG project addresses this gap by systematically investigating the impact of relativistic effects on MICD, bond properties, and NMR shifts in heavy-element compounds, with a focus on transition metal complexes. Employing state-of-the-art density functional theory (DFT) methods, the project aims to develop generalizable concepts across the periodic table and provide a detailed interpretation of these effects using molecular orbital theory. Advanced computational approaches, including fully relativistic four-component Dirac-Kohn-Sham theory, will enable precise quantification of SOR contributions. The research outcomes promise new insights into the role of relativistic effects in molecular magnetism, facilitating a deeper understanding of unusual NMR shifts and aromatic behavior in heavy-element systems.