Calculation of cross second virial coefficients using ab initio intermolecular potential energy surfaces for dimer H2-N2

The ab initio intermolecular pair potentials of dimerH(2)-N-2 were calculated from all constructed orientations, using the level of the theory CCSD(T) and basis sets aug-cc-pVmZ (m = 2, 3, 4, 23, 24, 34). The complete basis sets limit aug-cc-pVmZ (m = 23, 24, 34) were extrapolated by ab initio interaction energies at the level of the theory CCSD(T) with correlation-consistent basis sets aug-cc-pVmZ (m = 2, 3, 4). Then the quantum mechanical results were used for developing two new 5-site intermolecular potential functions by fitting ab initio intermolecular energies of dimer H-2-N-2. The ab initio fitted intermolecular potentials are used in standard thermodynamic relationships to get the cross second virial coefficients B-12(T) of the hydrogen-nitrogen mixture. The calculated results are in good agreement with the experimental data.