Original scientific paper

On Theoretical Evaluation of Equilibrium Thermodynamics and Kinetics of the Water Dimer and of the Second Virial Coefficient of Steam

Zdenek Slanina ; The J. Heyrovsky Institute of Physical Chemistry and Electrochemistry, Czechoslovak Academy of Sciences, Machova 7, CS-121 38 Prague 2, Czechoslovakia

Abstract

A quite recent new fitting of the MCY ab initio SCF Cl. potential energy hypersurface of (H20l2 has been systematically investigated using an automatic geometry optimization procedure employing analytically constructed gradients. The vibration analysis has been carried out for stationary points of the hypersurface based on analytical second derivatives of the energy with proper treatment of the eight redundancy conditions involved. The gas-phase thermodynamics of formation of the water dimer is described within a broad temperature interval on the basis of the thus-generated theoretical structural, vibrational, and energy data. The role of the water dimer in the real gas phase of water is analyzed and the contribution of (H20)2 to the second virial coefficient of ste am evaluated. Of the stationary points found, three have been identified as transition state s in water dimer
interconversions (autoisomerizations). The partial and overall
activation parameters are evaluated. Relationships between the
original and new fit results are studied systematically. The applicability
of both fits to various problems is briefly discussed. Throughout the whole study no empirical informa ti on was employed (with the exception of atomic masses, fundamental constants,a nd Coulomb's law).

Keywords

Hrčak ID:

177765

URI

https://hrcak.srce.hr/177765

Publication date:

31.10.1985.

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