Kinetic Isolation of Reaction Intermediates on Ice Surfaces. Precursor States of SO2 Hydrolysis

We studied the interaction of SO2 with ice films at temperatures above 80 K, with emphasis on the examination of the precursor states of SO2 hydrolysis, or SO2 surface complexes. Cs+ reactive ion scattering (RIS) and low energy sputtering (LES) techniques were used to examine the surface reaction products, in conjunction with temperature-programmed desorption (TPD) to monitor the desorbing species. The study indicated that the reaction of SO2 with the ice surface occurred through several distinct intermediate states, including a solvated SO2 species, a DSO2 species, and a strongly ionic molecular species, and these intermediates could be isolated on the ice surface due to kinetic trapping.