A NEW AB-INITIO BASED MODEL POTENTIAL FOR METHANE

We present a model potential for methane based on BSSE corrected MP3 r evel interaction energies of 132 methane dimers using the aug(df,pd)-6 -311G* basis set (6-311G** basis set augmented with diffuse d and f f unctions on carbon atoms and diffuse p and d functions on hydrogen ato ms). The density, heat of evaporation and self-diffusion coefficient o f liquid methane obtained by an MD simulation using the model potentia l reproduced the experimental values considerably better than the prev ious model potential based on MP3/6-311G(3d,3p) level interaction ener gies. (C) 1998 Elsevier Science B.V. All rights reserved.