(671d) Reaction Density Functional Theory and Its Application to Reactions in Aqueous Solution

Accurate determination of reaction barrier is crucial in the fields of chemical reaction engineering since it’s directly associated with the reaction rate and reaction path. Whereas massive quantum calculations relying on commercial softwares have been reported for understanding reaction mechanisms, very little attention has been paid to the solvent effect on the reaction barrier. The difficulty originates partially from the ill capture of inhomogeneous solvent structure around the reaction site. Herein, we propose a reaction density functional theory (RxDFT) developed by combining quantum density functional theory for calculating intrinsic reaction energy with classical density functional theory for addressing solvation contribution. For demonstration, two chemical reactions in aqueous solution are revisited by using RxDFT. We illustrate that the free energy profiles of reaction barrier/path can be well predicted, in comparison with the results of QM/MM simulation. Since no solvent molecule is explicitly considered, the developed RxDFT is promising to provide an efficient alternative to QM/MM approach or ab initio calculation.