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On the simultaneous description of h‐bonding and dipolar interactions with point charges in force field models
Author(s) -
Langenbach Kai,
Engin Cemal,
Reiser Steffen,
Horsch Martin,
Hasse Hans
Publication year - 2015
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.14820
Subject(s) - dipole , force field (fiction) , moment (physics) , polarity (international relations) , point (geometry) , point particle , field (mathematics) , chemical polarity , chemistry , polar , statistical physics , computational chemistry , molecular physics , thermodynamics , chemical physics , physics , classical mechanics , geometry , mathematics , quantum mechanics , biochemistry , organic chemistry , pure mathematics , cell
H‐bonding and polar interactions occur together in real fluids, but are of different nature and have different effects on macroscopic properties. Nevertheless, both are usually described by point charges in force field models. Despite this, the two effects can be separated. A simple model fluid is studied: a single Lennard‐Jones (LJ) site with two opposing point charges q placed in the center of the LJ site and at a distance d. By suitably varying both d and q, the dipole moment μ is kept constant. Both μ and d are systematically varied to study the properties of the resulting models, including H‐bonding, which is determined using a geometric criterion from literature. d can be used for tuning the H‐bonding strength and, thus, polarity and H‐bonding can be adjusted individually. The study of a second related model with symmetrically positioned point charges does not reveal this separation. © 2015 American Institute of Chemical Engineers AIChE J , 61: 2926–2932, 2015