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

We studied the interaction of SO 2 with ice films at temperatures above 80 K, with emphasis on the examination of the precursor states of SO 2 hydrolysis, or SO 2 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 SO 2 with the ice surface occurred through several distinct intermediate states, including a solvated SO 2 species, a DSO 2 species, and a strongly ionic molecular species, and these intermediates could be isolated on the ice surface due to kinetic trapping.