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Accuracy of typical approximations in classical models of intermolecular polarization.

Söderhjelm, Pär LU ; Öhrn, Anders LU ; Ryde, Ulf LU and Karlström, Gunnar LU (2008) In Journal of Chemical Physics 128(1).
Abstract
One of the largest limitations of standard molecular-mechanics force fields is the neglect of intermolecular polarization. Several attempts to cure this problem have been made, but the results have not always been fully satisfactory. In this paper, we present a quantitative study of the fundamental approximations that underlie polarization models for classical force fields. The induced charge density of a large set of molecular dimers is compared to supermolecular calculations for a hierarchy of simplified models. We study the effect of the Pauli principle, the local inhomogeneity of the electric field, the intramolecular coupling of the polarization response, and the fact that the induced density is a continuous function. We show that... (More)
One of the largest limitations of standard molecular-mechanics force fields is the neglect of intermolecular polarization. Several attempts to cure this problem have been made, but the results have not always been fully satisfactory. In this paper, we present a quantitative study of the fundamental approximations that underlie polarization models for classical force fields. The induced charge density of a large set of molecular dimers is compared to supermolecular calculations for a hierarchy of simplified models. We study the effect of the Pauli principle, the local inhomogeneity of the electric field, the intramolecular coupling of the polarization response, and the fact that the induced density is a continuous function. We show that standard point-polarizability models work rather well, despite their lack of all these effects, because (1) there is a systematic error cancellation between the neglect of effects of the Pauli principle and the locally inhomogeneous electric field, and (2) the lack of intramolecular coupling and the use of a dipole expansion of the induced density have only minor effects on the polarization. However, the cancellation in (1) is not perfect, and therefore polarizable force-fields could be improved if both effects are explicitly treated. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Chemical Physics
volume
128
issue
1
publisher
American Institute of Physics
external identifiers
  • wos:000252193700003
  • pmid:18190180
  • scopus:38049162158
ISSN
0021-9606
DOI
10.1063/1.2814240
language
English
LU publication?
yes
id
1ade24cf-79da-4a3d-a138-78dfd2826f09 (old id 1021443)
date added to LUP
2008-02-19 14:49:22
date last changed
2017-09-17 08:07:19
@article{1ade24cf-79da-4a3d-a138-78dfd2826f09,
  abstract     = {One of the largest limitations of standard molecular-mechanics force fields is the neglect of intermolecular polarization. Several attempts to cure this problem have been made, but the results have not always been fully satisfactory. In this paper, we present a quantitative study of the fundamental approximations that underlie polarization models for classical force fields. The induced charge density of a large set of molecular dimers is compared to supermolecular calculations for a hierarchy of simplified models. We study the effect of the Pauli principle, the local inhomogeneity of the electric field, the intramolecular coupling of the polarization response, and the fact that the induced density is a continuous function. We show that standard point-polarizability models work rather well, despite their lack of all these effects, because (1) there is a systematic error cancellation between the neglect of effects of the Pauli principle and the locally inhomogeneous electric field, and (2) the lack of intramolecular coupling and the use of a dipole expansion of the induced density have only minor effects on the polarization. However, the cancellation in (1) is not perfect, and therefore polarizable force-fields could be improved if both effects are explicitly treated.},
  articleno    = {014102},
  author       = {Söderhjelm, Pär and Öhrn, Anders and Ryde, Ulf and Karlström, Gunnar},
  issn         = {0021-9606},
  language     = {eng},
  number       = {1},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {Accuracy of typical approximations in classical models of intermolecular polarization.},
  url          = {http://dx.doi.org/10.1063/1.2814240},
  volume       = {128},
  year         = {2008},
}