Modeling Fickian Diffusion Coefficients of CO2-Water Mixtures Abbas Firoozabadi, Department of Chemical Engineering, Yale University A model for diffusion coefficient of CO2-H2O system , in gas, liquid or in supercritical state, should account for the polar nature of water molecules and polarizability of CO2 molecules. These effects, along with basic thermodynamic variables, may allow to predict diffusion coefficients of the CO2-H2O system over a broad range of pressure and temperature conditions encountered in the storage of CO2 in aquifers. Our proposed model is give below:   polarizability (m3) o  gas phase dipole moment (C.m)   dielectric constant   Lennard-Jones/Stockmayer length (m)