Title

Potential Energy Surface for Dispersion Interaction in (H2O)2 and (HF)2

Document Type

Article

Journal/Book Title

Journal of Physical Chemistry

Publication Date

1990

Volume

94

Issue

5

First Page

1781

Last Page

1788

DOI

10.1021/j100368a015

Abstract

The nonexpanded second-order dispersion energy is calculated for a number of geometrical configurations of ( H20)2 and (HF), within the framework of Sadlej’s “medium-polarized” basis sets. This treatment closely reproduces current benchmarks for the water dimer. In addition to monitoring the behavior of the dispersion energy as the proton donor and acceptor water molecule are misoriented from the linear geometry, this work examines a number of other structures such as the cyclic, stacked, and bifurcated dimers. The dispersion energy is shown to be highly anisotropic, generally favoring orientations that best allow overlap between occupied MOs of the two subunits; H-bonded geometries are favored over other structures. The computed dispersion energies of (H20), and (HF), are fit to an analytical potential involving isotropic atom-atom parameters. A model that combines UHwFith dispersion energy does not correctly reproduce the radial and angular dependence of the interaction energy when compared to Mdler-Plesset perturbation theory results.

Comments

Originally published by American Chemical Society in the Journal of Physical Chemistry.

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