The effect of perturbing gas density on the intensity distribution in rovibrational absorption bands

This paper aims at elucidating the mechanism for rotationally selective modification of rovibrational line intensities in linear molecules as a function of the perturbing rare gas density. The phenomenon of rovibrational line intensity damping is interpreted in terms of quasibound complexes and true bound complexes. The results of classical trajectory calculations are used to support the proposed model. The damping effect is tentatively connected to recent observations pointing at non-equilibrium abundances of molecular spin isomers in water molecules upon adsorption or aggregation.