Light-induced molecular processes on ice

The thesis "Light-induced molecular processes on ice" deals with two main issues: first, the interaction of water with a platinum surface, under very well-defined conditions (at liquid nitrogen temperature in a very low-pressure environment (Ultra-High Vacuum: pressure 2 x 10-11 mbar)), and second, the photochemistry of small, naturally occurring, organic molecules such as bromoform (CHBr3) molecules on ice surfaces. The first topic is of relevance for electrochemistry, where water-metal interactions are crucial in determining the system's reactivity. The second topic is relevant for our understanding of processes encountered in the Earth's atmosphere. In particular, for atmospheric chemistry, the fundamental steps of the photochemical reaction of bromoform on ice surfaces induced by UV light, are elucidated. This reaction constitutes an important step in the ozone depletion cycle, which greatly affects our atmosphere. Photodissociation studies reveal a rich UV-induced photochemistry of bromoform on ice: various direct fragmentation pathways, as well as formation of new, ice-mediated C—C and C—O bond containing chemical species. Given the previously reported detection of bromoform in the stratosphere, these observations may have significant implications for current models describing stratospheric ozone depletion.UBL - phd migration 201