Predicting CH/π Interactions with Nonlocal Density Functional Theory

• Published in: Chemphyschem Vol. 9; no. 6; pp. 891 - 895
• Main Authors: Hooper, Joe, Cooper, Valentino R., Thonhauser, Timo, Romero, Nichols A., Zerilli, Frank, Langreth, David C.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 21.04.2008; WILEY‐VCH Verlag; Wiley
• Subjects: Ab initio calculations; aromatic compounds; Atomic and molecular physics; Calculations and mathematical techniques in atomic and molecular physics (excluding electron correlation calculations); correlation energy; Coupled cluster theory; density functional calculations; Density-functional theory; Electronic structure of atoms, molecules and their ions: theory; Exact sciences and technology; hydrogen bonding; Physics; Correlation energy; Theoretical study; aromatic compounds; Pi electron system; Aromatics; density functional calculations; hydrogen bonding; Electron correlations; Electronic structure; Hydrogen bonds; Density functional method; Ab initio calculations; Coupled cluster method; Interaction energy; Organic compounds
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.200700715

We examine the performance of a recently developed nonlocal density functional in predicting a model noncovalent interaction, namely the weak bond between an aromatic π system and an aliphatic CH group. The new functional is a significant improvement over traditional density functionals, providing results which compare favorably to high‐level quantum‐chemistry techniques, but at considerably lower computational cost. Interaction energies in several model CH/π systems are in good general agreement with coupled‐cluster calculations, though equilibrium distances are consistently overpredicted when using the revPBE functional for exchange. The new functional predicts changes in energy upon addition of halogen substituents correctly. Accurate model: A new nonempirical density functional is used to model the weak bond between an aromatic π system and an aliphatic CH group (see picture). Interaction energies and the effects of halogen substituents compare favorably to high‐level quantum‐chemistry techniques, offering a promising and computationally tractable method for treating weakly bound molecular systems.