FLUORESCENCE YIELD NEAR EDGE STRUCTURE (FYNES) : A NOVEL TECHNIQUE FOR IN SITU SURFACE CHEMISTRY

Abstract

The Fluorescence Yield Near Edge Structure (FYNES) technique described represents a major advance in our ability to determine the hybridization and orientation of organic reaction intermediates in the presence of a reactive atmosphere. This technique uses synchrotron radiation in the soft x-ray region to create core holes in adsorbed molecules ; the decay of these core holes are then detected by their characteristic x-ray fluorescence during the deexcitation process. Since FYNES is a photon-in, photon-out spectroscopy, it is fully compatible with reactive gaseous environment. In situ experiments are described involving chemisorption, displacement, and dehydrogenation of organic molecules containing Carbon and Sulfur. The FYNES technique provides a unique opportunity for utilizing synchrotron facilities in characterizing surface intermediates and reaction rates on model catalyst surfaces in reactive environments.