Viabilty of atomistic potentials for thermodynamic properties of carbon dioxide at low temperatures

Investigation into volumetric and energetic properties of several atomistic models mimicking carbon dioxide geometry and quadrupole momentum covered the liquid–vapor coexistence curve. Thermodynamic integration over a polynomial and an exponential‐polynomial path was used to calculate free energy. Computational results showed that model using GROMOS Lennard–Jones parameters was unsuitable for bulk CO 2 simulations. On the other hand, model with potential fitted to reproduce only correct density–pressure relationship in the supercritical region proved to yield correct enthalpy of vaporization and free energy of liquid CO 2 in the low‐temperature region. Except for molar volume at the upper part of the vapor–liquid equilibrium line, the bulk properties of exp‐6‐1 parametrization of ab initio CO 2 potential were in a close agreement with the experimental results. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1772–1781, 2001