Studies of cluster ion-molecule reactions of atmospherically relevant specie

Since the discovery of the depletion of polar stratospheric ozone concentrations during early spring in 1986, great efforts have made to understand this phenomenon and determine if it could affect other areas of the globe. Heterogeneous reactions on cloud surfaces have been recognized as key factors in the conversion of inert reservoir species to those which catalytically destroy ozone. The use of cluster ion-molecule reactions as models of these systems allows for detailed examination of reaction mechanisms and reaction rates under well defined thermal conditions.;Investigation of the cluster ion-molecule reactions were performed on a variable temperature fast flow reactor coupled to a quadrupole mass spectrometer, capable of producing and evaluating the reactions of cluster ions at temperatures similar to those in the polar stratosphere. Modification to the Poorman's ion source and the reactant gas inlet allowed the study of many different cluster ions with the reservoir species, $rm Nsb2Osb5$ and ClONO$sb2$, without decomposition before their injection into the flow tube.;Study of cluster ion-molecule reactions with N$rmsb2Osb5$ revealed that nitric acid is formed as anticipated from the results of previous studies. The protonated water clusters required a minimum of 5 water molecules to react with N$rmsb2Osb5$, and the measured rate constants showed a dependence upon flow tube pressure. Anionic water clusters were observed to react with N$rmsb2Osb5$ to produce ions similar to those seen in the nitric acid studies.;Chlorine nitrate was found to not react with protonated water clusters under thermal conditions, which is contrary to results reported for studies utilizing techniques with high collision energies. Preliminary studies of hydrated cluster anions reactions with ClONO$sb2$ show rich chemistry that could mimic reaction sites on the surfaces of polar stratospheric clouds where species such as HCl have been dissociatively incorporated.