Campus Units

Chemistry

Document Type

Article

Publication Version

Published Version

Publication Date

5-2008

Journal or Book Title

Journal of Physical Chemistry A

Volume

112

Issue

22

First Page

4885

Last Page

4894

DOI

10.1021/jp801921f

Abstract

The dipole moment of the gas phase water monomer is 1.85 D. When solvated in bulk water, the dipole moment of an individual water molecule is observed to be enhanced to the much larger value of 2.9 ± 0.6 D. To understand the origin of this dipole moment enhancement, the effective fragment potential (EFP) method is used to solvate an ab initio water molecule to predict the dipole moments for various cluster sizes. The dipole moment as a function of cluster size, nH2O, is investigated [for n = 6–20 (even n), 26, 32, 41, and 50]. Localized charge distributions are used in conjunction with localized molecular orbitals to interpret the dipole moment enhancement. These calculations suggest that the enhancement of the dipole moment originates from the decrease of the angle between the dipole vectors of the lone pairs on oxygen as the number of hydrogen bonds to that oxygen increases. Thus, the decreased angle, and the consequent increase in water dipole moment, is most likely to occur in environments with a larger number of hydrogen bonds, such as the center of a cluster of water molecules.

Comments

Reprinted (adapted) with permission from Journal of Physical Chemistry A 112 (2008): 4885, doi:10.1021/jp801921f. Copyright 2008 American Chemical Society.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

Included in

Chemistry Commons

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