Density functional theory applied to proton-transfer systems. A numerical test

Abstract

The structure, interaction energy and proton-transfer features of the (H 5O 2 + complex are determined by using a nonlocal density functional theory method developed recently by Salahub and co-workers. The results are compared to those of a high- order Møller-Plesset electron-correlation calculation. The DFT calculation predicts correctly a symmetrical configuration of the complex at the equilibrium O—O distance, and yields a correct value of the H-bonding interaction energy. For a larger O—O separation, the electronic correlation effects on the double-well proton potential curve are overestimated in the DFT approach, whereas they are well reproduced by the second-order Møller-Plesset expansion.