M. S. Lazarus

X-ray photoelectron spectroscopy (XPS) studies of clean and hydrated TiO2 (rutile) surfaces

Abstract Using XPS, we have detected several oxygen sites on the surface of hydrated TiO2 (rutile) crystals. These sites are attributed to chemisorbed and physisorbed H2O. XPS spectra of clean TiO2 resulting from scraping in vacuum indicate that oxygens terminate at the very surface. Implications of these observations are discussed.

X-ray photoelectron spectroscopy (XPS) studies of hydrogen reduced rutile (TiO2-x) surfaces

Abstract XPS measurements have been made on reduced rutile surfaces under various conditions. It is found that upon exposure to H 2 O the amphoteric hydroxyl groups previously detected on the surface of the unreduced TiO 2 are not present in the reduced sample. Results and their consequences are discussed.

A study of shake-up satellites in Co 2p photoelectron spectra of trans-[Co(NH3)4Cl2]Cl and cis-[Co(NH3)4Cl2]Cl isomers

Abstract Mg Kα X-ray photoelectron (ESCA) spectra of the Co 2p levels have been obtained in trans - and cis -[Co(NH 3 ) 4 Cl 2 ]Cl isomers. It is observed that these compounds slowly decompose under X-ray irradiation. A procedure is employed to record real spectra for both the trans and cis isomers without any significant complication by the decomposition products. Three satellites are observed in both spectra at binding energies ≈ 4.8 eV, ≈ 9.3 eV, and ≈ 16.5 eV greater than that of the Co 2p 3 2 peak. These isomers are distinguished from one another by the sizable difference in the relative intensity of the first satellite to the main peak. The first two satellites are assigned to ligand to Co 3d shake-up transitions by use of symmetry arguments based on molecular orbital theory, while the origin of the third satellite is less certain. The implication of the results is discussed.