Potential energy surfaces of CF4, CCl4 and CBr4 dimers

Potential energy surfaces of CF4, CCl4 and CBr4 dimers were mapped with MP2/aug(df)-6-311G* ab initio calculations. Eleven different orientations were studied for each dimer. The potential well depth of the orientation with the strongest attraction was −0.681 kcal mol−1 for CF4, −2.862 kcal mol−1 for CCl4 and −3.702 kcal mol−1 for CBr4. The intermolecular potentials were represented by C-C, C-X (X = F, Cl, Br) and X-X interatomic potentials by applying the Morse potential model. The fitted model compared favourably with the ab initio energy surfaces.