Complexes and Clusters of Water Relevant to Atmospheric Chemistry: H2O Complexes with Oxidants
Experimental observations and data from quantum chemical calculations related to the complexes between water molecules and small oxygen containing inorganic species which are playing an important role as oxidants (O(1D), O(3P), O2(X3Σg), O2(b1Σg+), O3, HO, HOO, HOOO, and H2O2) in the atmosphere are reviewed with emphasis on their structure, hydrogen bonding, interaction energies, thermodynamic parameters and IR spectra. In recent years, weakly bound complexes containing water have increasingly attracted scientific attention. Water, in all its phases is a major player in the absorption of solar and terrestrial radiation. Thus, complexes between H2O and other atmospheric species may perceiveable influence the radiative balance and contribute to the greenhouse effect although their concentrations are low. In addition they can play an important role in the chemistry of the Earths atmosphere in particular in the oxidation of trace gases. Apart from gas phase complexes also the interactions of oxidants with ice surfaces have received considerable advertency lately due to their importance in the chemistry of snow, ice clouds and ice surfaces (e.g. ice shields in polar regions). In paleoclimate respectively paleoenvironmental studies, it is indispensable to understand the transfer processes from the atmosphere to the ice surface. Consequently, special attention is being paid here to the intercomparison of the properties of binary complexes and the complexes and clusters of more complicated composition including the oxidants adsorbed on ice surfaces, where ice is considered as a kind of large water cluster. Various facts concerning the chemistry of the atmosphere of the Earth (concentration profiles and possible influence on radical reactions in the atmosphere) are discussed.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL1-Processes and interactions in the polar climate system