CO2 solvation free energy using quasi-chemical theory.

Accumulation of greenhouse gases, especially carbon dioxide, is believed to be the key factor in global climate change. To develop effective ways to remove CO(2) from the atmosphere, it is helpful to understand the mechanism of CO(2) solvation first. Here we investigate the thermodynamics of CO(2) hydration using quasi-chemical theory. Two approaches for estimating hydration free energy are carried out. Both agree reasonably well with experimental measurements. Analysis of the free energy components reveals that the weak hydration free energy results from a balance of unfavorable molecular packing and favorable chemical association.