Ab initio quantum scattering calculations for modeling collision-perturbed spectra of atmosphere-relevant molecular systems*

An accurate description of collisional effects on the shapes of optical resonances is crucial for a reliable interpretation of molecular spectra and for reducing systematic errors in Earth’s

atmospheric measurements. We introduce a theoretical framework for describing the shape of molecular spectra, based on quantum scattering calculations and ab initio potential energy surfaces. We present computational tools developed in our group that address the challenges in solving coupled-channel equations in diatom-diatom systems. We discuss the application of this theoretical approach to collisional systems relevant to terrestrial atmospheric studies. In particular, we highlight our recent findings on the resonances in CO, O₂, and HCl, perturbed by collisions with the most abundant species of Earth’s atmosphere: N₂ and O₂.