Ab initio interaction potential of methane and nitrogen

A new global interaction potential for the CH4 and N2 complex has been derived at the MP2 level of theory and correlation consistent basis sets. The potential energy surface has been computed on a large grid of molecular geometries. In the most stable conformation, the nitrogen is below the methane pyramid base while the N–N bond axes and one of the methane C–H bonds are coplanar. The complete basis set limit of the interaction energies have been fitted to well-known analytical functions. Then the second virial coefficients were calculated for fitted potentials which agrees well with the experimental values.