Surface chemistry, mixed-valency, charge transfer and characterization studied by X-ray photoelectron spectroscopy

A variety of surfaces and surface systems have been studied predominantly using X-ray Photoelectron Spectroscopy (XPS). All experiments were carried out on a commercial surface analysis instrument modified to carry out specific experiments not possible in its "as purchased" configuration.; The effects of stoichiometry change and CO chemisorption on the surface electronic structure of the mixed-valence compound CeIr{dollar}sb2{dollar} have been studied. The surface iridium to cerium ratio can be varied by changing sample temperature while sputtering. Carbon monoxide is found to adsorb 80% molecularly on the surface. Stabilization of the (Xe) (5d6s){dollar}sp3{dollar}4f{dollar}sp1{dollar} configuration occurs due to an increase in effective nuclear charge on the cerium atom. Increased f-electron repulsion in the final state raises the energy of the f{dollar}sp2{dollar} final-state configuration and causes a 2.2eV shift to higher binding energy of the 3d{dollar}sb5{dollar}/{dollar}sb2{dollar}f{dollar}sp2{dollar} peak.; The surface of a computer magnetic hard disk has been characterized using Auger electron spectroscopy (AES), XPS and laser-induced thermal desorption (LITD) with Fourier transform mass spectrometric detection. AES and XPS reveal the presence of an oxidized silicon species. LITD at 5 MW/cm{dollar}sp2{dollar} power density produces spectra which have been identified as due to polydimethylsiloxanes on the sample surface.; The reaction product of H{dollar}sb2{dollar} + C{dollar}sb2{dollar}N{dollar}sb2{dollar} on the Pt(111) surface has been studied by XPS. Data from a series of anneal experiments carried out on this system are compared with that from two possible reaction products: HCN and ethylenediamine. H{dollar}sb2{dollar} + C{dollar}sb2{dollar}N{dollar}sb2{dollar} spectra show a strong similarity with ethylenediamine spectra and little similarity with HCN spectra. In conjunction with previous TDS and HREELS experiments the reaction product is determined to be a partially dehydrogenated ethylenediamine species.; Tetracyanoquinodimethane (TCNQ) has been studied by high resolution XPS. The N 1s spectrum reveals a sharp peak at 399.5eV with a shake-up excitation satellite 2.6eV to higher binding energy. The C 1s spectrum shows two main peaks at 286.6 eV and 285.3eV, but a single shake-up peak at 289.2eV. From this data it is concluded that the highest occupied and lowest unoccupied molecular orbitals of TCNQ are localized near the -CN ends of the molecule.