Basis set effects on the intermolecular interaction of the F 2–F 2 system

Abstract

Intermolecular potential energy surface (IPS) for F 2–F 2 system has been examined using RHF, MP2 and DFT-B3LYP methods. A number of basis sets from the double-zeta and triple-zeta family were used in order to evaluate the basis set effects. These effects vary with the level of theory used. Counterpoise (CP) correction has been used to show the extent of the basis set superposition error (BSSE) on the potential energy curves obtained for F 2–F 2 system. CP corrections revealed that B3LYP and RHF levels of theory predict a totally repulsive interaction between the two monomers of F 2–F 2 system. The deepest BSSE-corrected potential well have been obtained at MP2 level of theory with 6-31G* basis set. At RHF and B3LYP levels of theory the least repulsive BSSE-corrected potential have been obtained with 6-31G* basis set. Effects of basis set on the characteristics of the calculated IPS have also been analyzed based on the position of the potential minimum and its well depth as well as its corresponding hard sphere collision diameter.