High-Fidelity Surrogate Framework for Rapid Solvation of Gas-Phase and Interfacial Reaction Potential Energy Surfaces.

Abstract

Solvent can reorganize reaction paths and barriers, but bringing those effects into mechanistic calculations remains expensive, because every image in a solvated climbing-image nudged elastic band search requires a new self-consistent reaction-field calculation. Here, we present a high-fidelity surrogate framework that keeps a preconstructed nonsolvated reaction valley as the backbone and models only the geometry-dependent solvent contribution needed to transform it into the solution-phase potential of mean force, i.e., the solvent-shaped free-energy surface. Using uncertainty-selected evaluations with the plane-wave implicit solvation model based on electron density (PW-SMD), the method optimizes solvated reaction paths on the fly and recovers 300 K free-energy profiles from local surrogate Hessians. For 16 small-molecule reactions in water and 17 Cu(111) interfacial reactions, the framework reduces the average number of solvent-response calculations from 826.3 to 67.3 and from 1231.9 to 51.5, respectively, while maintaining small-molecule barrier differences of only 0.04 eV on average and an interfacial reaction barrier agreement within a few hundredths of an eV for most reactions. The surrogate also reproduces representative room-temperature activation and reaction free energies. These results show that solvent-induced reshaping of reaction pathways can be captured accurately from a sparse, strategically chosen set of solution-phase calculations, turning solvated reaction-path and free-energy calculations into a practical tool for molecular and interfacial mechanistic studies.