Kinetics of radical-molecule reactions in aqueous solution: A benchmark study of the performance of density functional methods

• Published in: Journal of computational chemistry 2014-10, Vol.35 (28), p.2019-2026
• Main Authors: Galano, Annia, Alvarez-Idaboy, Juan Raúl
• Format: Article
• Language: English
• Subjects: Approximation; Aqueous solutions; Benchmarks; density functional theory; dispersion; empirically fitted parameters; exact exchange; long-range correction; Molecular chemistry; Molecules; rate constants; Reaction kinetics
• ISSN: 0192-8651; 1096-987X
• DOI: 10.1002/jcc.23715

The performance of 18 density functional approximations has been tested for a very challenging task, the calculations of rate constants for radical‐molecule reactions in aqueous solution. Despite of the many difficulties involved in such an enterprise, six of them provide high quality results, and are recommended to that purpose. They are LC‐ωPBE, M06‐2X, BMK, B2PLYP, M05‐2X, and MN12SX, in that order. This trend was obtained using experimental data as reference. The other relevant aspects used in this benchmark are: (i) the SMD model for mimicking the solvent; (ii) the conventional transition state, the zero‐curvature tunneling correction, and the limit imposed by diffusion for the calculation of the rate constants. Even though changing any of these aspects might alter the trend in performance, at least, when using them, the aforementioned functionals can be successfully used to obtain high quality kinetic data for the kind of reactions investigated in this work. © 2014 Wiley Periodicals, Inc. Six density functional approximations are recommended for kinetic calculations in aqueous solution: LC‐ωPBE, M06‐2X, BMK, B2PLYP, M05‐2X, and MN12SX, in that order. This result was obtained using the SMD model, conventional transition state theory, zero‐curvature tunneling correction, and experimental data as reference.