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Intermolecular forces in van der waals dimers
Author(s) -
Hurst G. J. B.,
Fowler P. W.,
Stone A. J.,
Buckingham A. D.
Publication year - 1986
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560290520
Subject(s) - van der waals force , intermolecular force , chemistry , perturbation theory (quantum mechanics) , electrostatics , ab initio , van der waals surface , molecule , ab initio quantum chemistry methods , hard spheres , van der waals radius , van der waals strain , computational chemistry , chemical physics , physics , quantum mechanics , organic chemistry
For several van der Waals molecules, the results of ab initio intermolecular perturbation theory are compared with the simple Buckingham‐Fowler model. A selection of dimers is studied, with emphasis on cases where the experimental structure is not reliably predicted by the hard‐sphere electrostatic model. Cases are reported where the electrostatic term dominates, in agreement with the model: HF···HF, H 3 N···HF, N 2 O···HF, and H 2 CO··· HF; cases where the electrostatic term dominates but the molecular shapes are not well described by hard spheres: CO 2 ···H 2 O and CIF···HF; and cases where there is a delicate balance between the electrostatic and other terms:H 2 O···HF, H 2 O···HCCH, CO 2 ···HF, CO 2 ···N, and CH 3 CN···HCN. It is concluded that, in general, the electrostatic interaction is central to the strength and orientation dependence of the forces between molecules and that the model provides a useful approximation to this interaction, while perturbation theory gives a more complete picture.