Investigating Solvent Effects on the Magnetic Properties of Molybdate Ions (Moo_4^2-) with Relativistic Embedding

We investigate the ability of mechanical and electronic density functionaltheory (DFT)-based embedding approaches to describe the solvent effects onnuclear magnetic resonance (NMR) shielding constants of the ^95Mo nucleusin the molybdate ion in aqueous solution. From the description obtained fromcalculations with two- and four-component relativistic Hamiltonians, we findthat for such systems spin-orbit coupling effects are clearly important forabsolute shielding values, but for relative quantities a scalar relativistictreatment provides a sufficient estimation of the solvent effects. We find thatthe electronic contributions to the solvent effects are relatively modest yetdecisive to provide a more accurate magnetic response of the system, whencompared to reference supermolecular calculations. We analyze the errors in theembedding calculations by statistical methods as well as through a real-spacerepresentation of NMR shielding densities, which are shown to provide a clearpicture of the physical processes at play.