Driving and probing surfaces with light

Abstract

Surfaces play an important role in chemical reactions: the metal surface in the car exhaust catalyst reduces the amount of harmful species. In the interstellar medium and the earth's stratosphere, ice surfaces play an important role both by the formation of molecules and by the destruction of ozone in the atmosphere. To understand reactions on a surface it is essential to know the structure of the surface and the interaction of the surface with adsorbed species. The first part of this thesis describes a study of the surface of an ice film. The surface of the film can change before the bulk of the ice film changes. This surface structure - chaotic or ordered - determines the reactivity of the surface and has therefore important consequences for reactions in the interstellar medium and the earth's stratosphere. To better understand the interaction between the surface and the adsorbed particles the energy transfer between these two has been studied. As described in the second part of this thesis, this energy transfer depends strongly on how and where the molecules are adsorbed on the surface - on atomic length scale. This fundamental study is possibly relevant for the development of new chemical processes, in which the use of sunlight plays an important role and for the further development of the car exhaust catalyst.