The role of complexes of water and carbonyl containing molecules in the atmosphere

In this work, we study the binary complexes of water with formaldehyde, acetaldehyde and acetone using density functional theory. The highest level of theory we used was the B3LYP/6-311++G(3df,3pd). At this level of theory, the computed binding energies were 2.6 kcal mole(-1) for water-formaldehyde, 3.5 kcal mole(-1) for water-acetaldehyde and 3.9 kcal mole(-1) for water-acetone. We also compute vibrational and rotational frequencies and compare the former to matrix isolation experiments when possible. Equilibrium constants for the formation of these complexes are calculated from the data, as well as rate constants for the dissociation of the complex. Some speculation can be made using this data as to the effect these complexes may have on atmospheric chemistry. (C) 2000 Elsevier Science Ltd. All rights reserved.