(184e) New Perspectives on Aqueous Phase Reaction Mechanisms with Ab Initio Molecular Dynamics, Nudged-Elastic Band, and Wavefunction Theory-in-DFT Embedding

Groenenboom, M., University of Pittsburgh
Keith, J. A., University of Pittsburgh

Quantum chemistry is more frequently used as a powerful tool to model physical phenomena, but the quality of predictions depend on the model’s ability to capture the underlying physics of the chemical system. This presentation will detail recent work investigating an aqueous phase reaction mechanism, the chemical reduction of CO2 with sodium borohydride, and its sensitivity on the method employed when modeling it. Continuum solvation methods are widely used when modeling aqueous phase reaction mechanisms, but it is known that they may not capture effects of explicit hydrogen bonding present in models utilizing periodic boundary conditions and incorporating explicit solvent molecules in the simulation. On the other hand, periodic boundary calculations normally utilize conventional GGA exchange-correlation (XC) functionals, but these often provide unsatisfactory accuracy when used to model molecular energies. We present a comparative benchmark study to illustrate how different methods treat the underlying physics of aqueous phase chemical reactions. We also illustrate the utility of Manby and Miller’s ab initio Wavefunction Theory-in-DFT Embedding calculation schemes for benchmarking and diagnosing the need for DFT+X in applications.