Title

Factors Contributing to Distortion Energies of Bent H-Bonds. Implications for Proton Transfer Potentials

Document Type

Article

Journal/Book Title

The Journal of Physical Chemistry

Publication Date

8-1989

Publisher

American Chemical Society

Volume

93

Abstract

The ab initio interaction energy for the optimal arrangement of a number of H-bonded systems is decomposed qnd compared to a variety of geometries in which angular deformations are imposed. For cationic systems (H3NH-NH3)+ and (H20H...0H2)+, the (HOH...OH)- anion, and the neutral dimer (HOH-OH2), the electrostatic term is the largest of the various components and provides a reasonable first approximation to the total interaction energy as a result of mutual cancellation between the remaining terms. Even though the multipole expansion of the electrostatic interaction is not rapidly convergent, its cumulative sum through R-5 offers a good approximation to the full electrostatic expression. Most of the distortion energy resulting from angular deformation of the H bond in (HOH...OH)- is concentrated in the dipole-ion term. The same is true of the cationic systems except that the ion-quadrupole term is of comparable magnitude and should be considered as well. In all these cases, a simple picture based on the preceding interactions is usually capable of predicting the sense of the asymmetry introduced into the proton-transfer potential by a given angular distortion.

Comments

Originally published in The Journal of Physical Chemistry by the American Chemical Society . Publisher’s PDF available through remote link. DOI: 10.1021/j100354a055