Dimers of the major components of the atmosphere: Realistic potential energy surfaces and quantum mechanical prediction of spectral features

Accurate potential energy surfaces for the N-2-N-2 and N-2-O-2 dimers have been obtained from the analysis of scattering experiments from our laborato ry, and of available second virial coefficient data. A harmonic expansion f unctional form describes the geometries of the dimers and accounts for the relative contributions to the intermolecular interaction from components of different nature. Together with the previously obtained singlet, triplet a nd quintet O-2-O-2 surfaces, where the role of spin-spin coupling was also considered, the new surfaces allow the full characterization of structure a nd internal dynamics of the clusters, whose bound states and eigenfunctions are obtained by exact quantum mechanics. Besides the information on the na ture of the bond, these results can be of use in modelling the role of dime rs in air. The calculated rotovibrational levels also provide a guidance fo r the analysis of spectra, thus establishing the ground for atmospheric mon itorings.