Conventional XPS Research Articles

High energy xps using a monochromated Ag Lα source: resolution, sensitivity and photoelectric cross sections

Resolution, sensitivity and calibration data are presented for a novel high energy XPS source, monochromated Ag Lα radiation ( hv = 2984.3 eV). Adequate resolution is attainable for good signal/noise spectra, whilst values for experimental sensitivity factors agree well with theoretical cross section values calculated by Nefedov. This allows an evaluation of ESCA 3 Mk. II transmission function up to 3000 eV, which appears to obey an approximate E −1 2 dependence. Monochromated Ag Lα (linewidth 1.3 eV) overcomes the problem of broad natural linewidths for high energy sources, such that chemical state information can be gained. Various new core level and Auger peaks are developed, a notable feature being the 1s core level and KLL Auger transition capability from Al through to Cl. Improved sensitivity is experienced for elements whose major peaks occur in the 1500–3000 eV BE range, whilst there is no serious reduction of sensitivity in the conventional XPS energy range.

Photoionization study of the CN anion: A study of the NaCN(001) surface in comparison with CO and N 2

The results of a combined synchrotron UV-radiation and conventional XPS study on the (001) surface of a NaCN single crystal are reported. Absolute valence and core binding energies of CN − are deduced. The valence electron spectrum of NaCN is shown to be dominated by emission from the CN − sublattice. Satellite structure is found in the inner valence electron region and consistently interpreted in comparison with CO and N 2. The experimentally determined electronic structure is compared with many-body ab initio calculations of the ionization spectrum of CN −. No band structure effects ( k dispersion) in the valence spectra are found due to the rotational disorder of the CN sublattice. The branching ratios of the outer valence levels are determined, and shape resonances in both σ levels are observed. The energies of the shape resonances in CN − are compared with gaseous, condensed and adsorbed CO and N 2.

Imaging XPS—A new technique, I—principles

AbstractXPS imaging promises to be a powerful analytic tool because it enables specific information on both elements and bonding to be recorded on a two‐dimensional distribution map. As far as the authors are aware, the only scanning XPS method to date which has been found to be practical is essentially a scanned‐particle‐beam method, like scanning AES, and it is only applicable to thin film specimens. This paper provides the basic ideas of a new imaging XPS technique based on a quite different concept. It will be applicable to any kind of specimen that can be analysed in a conventional XPS system. It makes use of the dispersion properties of a spherical condenser‐type spectrometer and applies a two‐dimensional electron detection device for decoding the energy and emission position of an analysed photoelectron. Experimental arrangement and theory of operation are presented.