Our research is focussed upon the application of first-principles theory and ultra-high-vacuum single-crystal experiments to problems in surface chemistry and catalysis. We make use of fibre-optic low-energy electron diffraction (FO-LEED) to obtain structural information, reflection absorption infra-red spectroscopy (RAIRS) to obtain vibrational information, single-crystal adsorption calorimetry (SCAC) to obtain energetic information, supersonic molecular beams (SMB) to obtain kinetic information, and low- temperature scanning tunnelling microscopy (LT-STM) to obtain morphological, topographic and electronic information about surfaces and the molecules that adsorb, diffuse and react upon them. Density functional theory (DFT) provides a framework within which to calculate comparable data, which aids in the interpretation of our experimental work.