H ��� H model potential for exchange-repulsion energy of methane dimer

Abstract

The procedure previously proposed for the parameterization of the exchange–repulsion energy using probe atom calculations is applied here to the study of the methane dimer and refined to give a very accurate anisotropic model potential in terms of atomic parameters. The most accurate model uses sites on C and H atoms and requires 12 parameters, but a description using just four isotropic sites shifted inward from the H atoms by 15% of the bond length is almost as accurate and is very simple in form. © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 847–857, 1998