Infrared and Photoelectron Spectroscopic Studies of Adsorbates on Solid Surfaces: Experiments and DFT Calculations

Sammanfattning: In general, the more complex and real a system is, with all its interactions with solvents and contaminations etc., the harder it is to accurately model it and reproduce the experimental results by calculations. Similarly, modern sophisticated, advanced and higher order calculations are done for very specialized systems, often removed from any experimental equivalent. This dissertation deals with the description of chemistry and physics of adsorbed molecules on solid surfaces from a theoretical as well as experimental point of view, using density-functional calculations together with vibrational and photoelectron spectroscopy of model systems. These model systems have made it possible to let the calculations and experiments effectively overlap, for example, to accurately describe the anharmonic behaviour of the vibrational transitions. The calculations have been performed using density-functional theory methods for adsorbate/surface systems represented by clusters. In the course of the dissertation an effort has been to increase the accuracy of the calculations. The result was that the surface vibrational spectra of two model systems, methoxy and carbon monoxide adsorbed on Cu(100), were accurately reproduced. The ethanol oxidation on Rh(111), forming adsorbed acetate, was studied by photoelectron spectroscopy, Fourier transform infrared spectroscopy and calculations. Adsorbed water have been studied by DFT calculations, surface vibrational spectroscopy as well as with photoelectron spectroscopy. In the former case the growth, self-diffusion and H/D exchange of very thin films (< 50 Å) of amorphous solid water vapor, deposited on Cu(100), were investigated by Fourier transform infrared spectroscopy and water-dimer DFT calculations. In the latter case the dissociative and non-dissociative adsorption of water on reconstructed TiO2(001)-(4x1) films, grown by chemical vapor deposition, was studied by photoelectron spectroscopy.