Computational studies of atmospheric chemistry species: Part 7. An ab initio study of the N2·O2 heterodimer2

Abstract The singlet and triplet potential energy surfaces for the N 2 ·O 2 heterodimer have been investigated at the Hartree-Fock level of theory employing the 4-31G and 6-31 + G ∗ basis sets. Four stationary points exhibiting linear, T-shaped and parallel Symmetric configurations have been located and characterized according to the eigenvalues of the Hessian matrix. Electron correlation effects, which play a fundamental role for weakly bound complexes, have been accounted for at the Meller-Plesset second-order perturbation theory (MP2) level with the 6-31 + G ∗ basis set. The triplet N 2 ·O 2 heterodimers are predicted to be stable bound systems, with the singlet complexes being unstable with respect to the isolated monomer subunits.