No abstract

This Account describes a recent study of reactions on ice surfaces with the emphasis on the mechanistic features of elementary reactions steps. Cs(+) reactive ion scattering (Cs(+) RIS) and low-energy sputtering (LES) techniques monitor the reactions by detecting the molecules and ions on the ice surface. The types of reactions include molecule diffusion and migration, proton transfer, and some simple reactions on frozen water and alcohol surfaces. Ice surface reactions exhibit unique behaviors due to a kinetic constraint, resulting in the isolation of reaction intermediates, preferential stabilization of charged species, and diversity of reaction products.

Figure 2. Ion/surface collision spectrum recorded after collision of 30 eV benzene molecular ions at an H-SAM surface. The ion at m/z 91 corresponds to the addition of a methyl group followed by loss of H 2 and that at m/z 65 to further loss of C 2 H 2 . The peak at m/z 79 is due to a H atom abstraction reaction. The inset shows the collision process and some reaction products. Reprinted from ref 72.

No abstract

Ice surfaces offer a unique chemical environment in which reactions occur quite differently from those in liquid water or gas phases. In this article, we examine the basic properties of ice surfaces below the surface premelting temperature and discuss some of the recent investigations carried out on reactions at the ice surfaces. The static and dynamic properties of an ice surface as a reaction medium, such as its structure, molecule diffusion and proton transfer dynamics, and the surface preference of hydronium and hydroxide ions, are discussed in relation to the reactivity of the surface.