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Nonbonded interactions. 1. Anisotropic hydrogen‐hydrogen interactions
Author(s) -
Wiberg Kenneth B.,
Murcko Mark A
Publication year - 1987
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.540080809
Subject(s) - ab initio , hydrogen , chemistry , anisotropy , molecule , hydrogen bond , atomic physics , computational chemistry , basis set , ab initio quantum chemistry methods , field (mathematics) , function (biology) , physics , density functional theory , quantum mechanics , mathematics , evolutionary biology , pure mathematics , biology , organic chemistry
The hydrogen‐hydrogen nonbonded potential which may be derived from the calculated interactions between hydrogen molecules has been obtained. The best three‐parameter Buckingham function gave an RMS error of 0.18 kcal/mol in fitting Price and Stone's ab initio data for 130 pairs of hydrogen molecules, which may be compared with an RMS error of 0.74 kcal/mol using the parameters in the MM2 force field. Burton's basis set is also considered. A better fit to these data requires that the angular relationship between the bonds be included. The data for hydrogen as well as experimental data for chlorine show that these atoms appear “larger” normal to the bond axis than along the axis, and this is probably also the case for other atoms. When simple angular terms are added it is possible to fit the Price and Stone data set with an RMS error of less than 0.06 kcal/mol. The preferred function was: V = [ a 0 + a 1 (sin θ 1 + sin θ 2 ) 4 + a 2 r ] e −3 r − [ c 0 + c 1 (1 + sinθ 1 sinθ 2 )]/ r 5 . Deficiencies in the current ab initio data are discussed.