COMP 335 |
| Intermolecular complexes of sulfur trioxide and water are important species in atmospheric chemistry, for example in the formation of acid rain. Heterogeneous chemistry, including reactions taking place on ice surfaces, plays a key role in reactions of sulfur oxides in the atmosphere since it is estimated that 50 percent of atmospheric sulfur dioxide reactions occur heterogeneously. In this work, we report on the results of density functional theory studies of sulfur trioxide interacting with large water clusters of up to 39 water molecules in order to model the interaction with an ice surface. Results have been obtained at the B3LYP/6-31G(d) level of theory. Optimized geometries and vibrational frequencies have been computed for all structures, and minima on the potential energy surface as well as transition states for conversion to sulfuric acid have been located. The calculated binding energy of sulfur trioxide to the water clusters ranges from 13-20 kcal/mol and the activation barrier for conversion to sulfuric acid ranges from 3-6 kcal/mol. The results will be correlated with previous studies of the interaction of sulfur trioxide with small water clusters. |
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Poster Session
6:00 PM-8:00 PM, Tuesday, August 21, 2007 BCEC -- Ballroom Foyer, Poster
Sci-Mix
Division of Computers in Chemistry |