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Variation of atomic charges during proton transfer in hydrogen bonds
Author(s) -
FloriáN Jan,
Scheiner Steve
Publication year - 1994
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540150507
Subject(s) - chemistry , formamide , ionic bonding , proton , hydrogen bond , ab initio , intermolecular force , ammonia , ab initio quantum chemistry methods , mulliken population analysis , population , computational chemistry , chemical physics , ion , molecule , density functional theory , physics , demography , organic chemistry , quantum mechanics , sociology
The point atomic charges in a number of ionic H‐bonded systems are studied by ab initio calculations as functions of the proton transfer coordinate. In the proton‐bound complexes of water–water, ammonia–ammonia, formamide–water, formamide–ammonia, and dimethylether–ammonia, the net atomic charges were obtained using Mulliken population analysis and from the diagonal elements of the atomic polar tensors calculated at the HF/4–31G and MP2/6–31 + G** levels. The dependence of the atomic charges upon the coordinate of the transferring proton was found to be close (within an error of 0.02 e) to a linear function for intermolecular distances in the 2.5–2.8 Å range. The obtained charge and charge flux dependencies highlight the electron redistribution during the proton transfer process and provide insights into the source of the high infrared (IR) intensities of stretching modes of NH and OH bonds undergoing hydrogen bonding. © 1994 by John Wiley & Sons, Inc.