Quantifying Uncertainties in Solvation Procedures for Modeling Aqueous Phase Reaction Mechanisms

Computational quantum chemistry provides fundamental chemical and physical insights into solvated reaction mechanisms across many areas of chemistry, especially in homogeneous heterogeneous renewable energy catalysis. Such reactions may depend on explicit interactions with ions solvent molecules that are nontrivial to characterize. Rigorously modeling effects molecular dynamics usually brings steep computational costs while the performance continuum models such as polarizable model (PCM), charge-asymmetric nonlocally determined local-electric (CANDLE), conductor-like screening for real solvents (COSMO-RS), effective medium method reference interaction site (ESM-RISM) less well understood mechanisms. Here, we revisit a aqueous hydride transfer reaction—carbon dioxide (CO2) reduction by sodium borohydride (NaBH4)—as test case evaluate how different perform phase charge migrations would be relevant catalysis For this system, mechanics/molecular mechanics (QM/MM) simulations almost exactly reproduced profiles from QM simulations, Na+ counterion QM/MM plays an insignificant role over ensemble averaged trajectories describe pathway. However, used static calculations gave much more variability data depending whether system was modeled using shells and/or counterion. We pinpoint due unphysical descriptions charge-separated states gas (i.e., self-interaction errors), show accurate hybrid functionals lessens these errors. This work closes recommended procedures treating solvation future efforts studying