Shapes of optical molecular resonances from first principles: calculations for atmosphere-relevant molecular systems

We present the results of the investigation of the line-shape parameters for two atmospheric systems based on ab initio quantum-scattering calculations. The first one is the N2-perturbed CO molecule, for which we investigated the R(0) purely rotational line. We use three recently reported potential energy surfaces (PESs), calculated by means of the state-of-the-art quantum chemistry methods, to determine the pressure broadening coefficient. We obtain reasonable agreement with the experimental data. The second system is the N2-perturbed O2 molecule. We employ the same methodology, generalized for the case of the active molecule in the $^{3}\Sigma$ electronic ground state. This is the first ab initio investigation of the line-shape parameters in the O2-N2 system. The data provided through the investigation of both systems is important for terrestrial atmospheric measurements, and can be used for populating the HITRAN database.