Theoretical investigation of the Ca+–N2 and Ca2+–N2 complexes

The structures, harmonic frequencies and binding energies for the ground states of Ca+–N2 and Ca2+–N2 are computed at several theoretical levels, including Møller–Plesset second-order perturbation with full electron correlation and density functional theory. The charge–quadrupole interaction yields linear geometries as minima for both complexes, while the C2v geometries are transition states. At the MP2 level, Ca+–N2 has a dissociation energy (De) of 5.3 kcal/mol and a Ca+–N bond distance of 2.78 Å. Ca2+–N2 has a dissociation energy (De) of 23.8 kcal/mol and a shorter metal–ligand bond of 2.48 Å.