Document Type

Article

Original Publication Date

1994

Journal/Book/Conference Title

The Journal of Chemical Physics

Volume

100

Issue

7

DOI of Original Publication

10.1063/1.467187

Comments

Originally published at http://dx.doi.org/10.1063/1.467187

Date of Submission

October 2015

Abstract

Ab initio 6‐31G** electronic structure calculations have been used to determine the minimum energy geometries and vibrational frequencies of molecular clusters of water and carbon dioxide. Application of statistical thermodynamics leads to theoretical equilibrium constants for gas phase dimerization of water and the formation of an adduct of carbon dioxide with water.The low energy vibrations of the clusters lead to much larger contributions to the vibrational partitioning of the energy than do the fundamental vibrations of the monomeric species. A new ‘‘Harmonic‐Morse’’ formula is derived to estimate anharmonicity from optimized harmonic frequencies and two additional values on the potential surface for each vibration. These ab initiocalculations of equilibrium constants are very close to recent measurements and fall within the range of values obtained by other methods. This no‐parameter treatment gives excellent agreement for the equilibrium of H2O–CO2 near the supercritical fluid range of CO2 and suggests that a ‘‘Theory of Significant Clusters’’ may be extended to a model of supercritical fluids which includes the effects of anharmonicity.

Rights

Zhang, N. R., and Shillady, D. D. AB-INITIO EQUILIBRIUM-CONSTANTS FOR H2O-H2O AND H2O-CO2. The Journal of Chemical Physics, 100, 5230 (1994). Copyright © 1994 American Institute of Physics.

Is Part Of

VCU Chemistry Publications

Included in

Chemistry Commons

Share

COinS