Global fits of new intermolecular ground state potential energy surfaces for N2-H2 and N2-N2 van der Waals dimers

Abstract We have built new global fits for the ground state potential energy surfaces (PES) of N 2 –H 2 and N 2 –N 2 complexes using ab initio perturbative and supermolecular methods. The analytical expressions used in the four-dimensional fitting procedure require the knowledge of the multipole moments, the static and dynamic multipolar polarizabilities of each monomer, from which long-range electrostatic, induction and dispersion coefficients are evaluated. In agreement with previous work, we have found the most stable conformation of N 2 –H 2 to be linear and that of N 2 –N 2 to have a 45/50° canted parallel shape. The quality of present PESs have been checked by comparing between calculated and experimental second virial coefficients and integral scattering cross-sections, which are found to be in good agreement.

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