Hybrid discrete-continuum solvation methods

Hybrid discrete-continuum approaches for solvation have been widely applied for diverse problems in chemistry suck as pK(a) calculation in aqueous and nonaqueous solvents, activation free energy barriers for ionic processes in solution, and surface reactions. A special version of this approach, the cluster-continuum quasichemical model, has also been used for establishing a single-ion solvation free energy scale in different solvents compatible with the tetraphenylarsonium tetraphenylborate assumption. The use of discrete-continuum solvation methods can lead to meaningful improvement with respect to pure continuum solvation models for modeling diverse chemical process in solution. In the case of pK(a) calculations, there are cases where the root mean squared error is as large as 7 pK(a) units with pure continuum solvation model and becomes around 1 pK(a) unit with the hybrid approach. For complex reactions in solution, errors as large as 10 kcal/mol for activation free energies with the pure continuum approach can be substantially reduced with the inclusion of explicit solvent molecules. A discussion of the theory of hybrid discrete-continuum methods is also presented and further development is expected in the coming years. This article is categorized under: Structure and Mechanism > Reaction Mechanisms and Catalysis Software > Quantum Chemistry Molecular and Statistical Mechanics > Free Energy Methods