van der Waals Complexes of Water with Oxygen and Nitrogen:  Infrared Spectra and Atmospheric Implications

Weakly bonded complexes of water with oxygen and nitrogen are studied using ab initio methods; their thermodynamic functions and infrared spectra are calculated. Infrared spectra for these complexes exhibit several interaction-induced low-frequency modes, while their estimated atmospheric fractions appear to be larger than for many recognized “greenhouse” species. This implies that atmospheric H 2 O−O 2 and H 2 O−N 2 complexes may absorb more of the earth's surface radiation than individual molecules and thus contribute to a “greenhouse” effect.