An ab initio study of the binding of N₂ to Na⁺ and K⁺

The binding energies of N₂ to Na⁺ and K⁺ are computed, using the SCF supermolecule approach with extended basis sets together with the counterpoise correction computed in two extreme ways, and supplemented by a perturbation calculation of the dispersion energy. Inclusion of the calculated zero-point energy and the additional correction due to the variation of the correlation in N₂ upon complexation leads to an Na⁺-N₂ binding of -7.9 to -8.1 kcal/mole (compared to a measured enthalpy of -8 ± 0.5) and to a corresponding theoretical value computed for K⁺-N₂ of -4.6 to -4.8 kcal/mole.