Parametric representation of the low-energy portion of the water-carbon dioxide G3( MP2)//B3LYP electronic energy surface. Variations on the theme developed by Professor B. Widom in his PhD dissertation

The G3( MP2)//B3LYP electronic energy surface for CO2/H2O adducts was determined for energies less than 10 kcal/mol with the distance between the water oxygen and the carbon atom between 2.0 and 8.0 angstrom. This 12-dimensional low-energy surface was fitted to a number of linear parametric schemes, and the parameters for the best two are reported here. The structures and energies for the derived pair of minima closely reproduce the high level ab-initio calculations. The two parametric representations are suitable for use in Monte Carlo or molecular dynamics calculations.