I. Cserny

The role of oxide layer formation during corrosion inhibition of mild steel in neutral aqueous media

Abstract The influence of phosphonic acid with Ca cation on iron surfaces in neutral aerated media (0.5 mol dm − NaClO 4 ) has been studied by electrochemical and surface analytical methods. X-ray induced photoelectron (XPS) and Auger electron spectroscopy (XAES) provided the possibility for identification of different chemical states of the constituents of the corrosion protective layers. The presence of certain cations led to a synergistic effect. It was found that calcium ions were incorporated into the film that developed on the mild steel surface, containing a mixed oxide and hydroxide complex. Electrochemical Impedance Spectroscopy (EIS) was used to determine the inhibitor efficiency of phosphonic acid at different concentrations. The data obtained were fitted and modelled by an equivalent circuit model.

Electrostatic spectrometer for measurement of internal conversion electrons in the 0.1–20 keV region

Abstract A new second order focusing, n = 1.5 cylindrical mirror electron spectrometer has been built. It enables us to measure the electrons emitted from the radioactive sources in the 0.1–20 keV region with an instrumental energy resolution of 0.1-1%. The ring-shaped input slit serving as a virtual electron optical object together with the large dimensions of the analyser (the total focal length equals 525 mm) allow us to utilize sources up to 1.5 cm 2 area. The spectrometer was adjusted using electron guns and tested also by 57 Co and 169 Yb radioactive sources prepared by vacuum evaporation and mass separation. The instrument operates automatically at oil-free vacuum of 4 × 10 −6 Pa and the electron spectra are scanned in cycles. The background of the channeltron is about 1.5 counts/min.

High-Resolution Photoemission and Auger Parameter Studies of Electronic-Structure of Tin Oxides

The electronic structure of metallic Sn, polycrystalline Sn oxides, and (110) natural single crystal SnO2 (cassiterite) was studied by high resolution measurements of core and valence photoemission, photoinduced Auger spectra, and energy loss spectra. The advantage of in vacuo scraping in obtaining SnO surfaces is shown in comparison with surface cleaning by ion sputtering. Valence band x‐ray photoemission spectroscopy spectra are interpreted by a cluster‐type discrete variational Xα molecular orbital model, revealing the change in the electronic structure which leads to an increased conductivity. The use of the Auger parameter approach in gaining information on the initial and final state effects, ligand polarizability, and final state hole–hole repulsion energies are demonstrated for the case of tin oxides.

The effect of calcium ions on the adsorption of phosphonic acid: a comparative investigation with emphasis on surface analytical methods

Abstract The influence of calcium ions on the adsorption of 1-hydroxy-ethane-1,1-diphosphonic acid (HEDP) on Fe electrodes has been examined. Surface analytical methods (XPS and XAES) have been applied in order to obtain direct information on the structure of the surface layer. On the surfaces of electropolished samples, various Fe 2+ , Fe 3+ and FeOOH compounds as well as the metallic state of Fe could be identified in the surface layers. HEDP was adsorbed on the iron surface in almost the same extent, when the basic solutions were bidistilled water or 0.5 mol dm −3 NaClO 4 , respectively. The presence of Ca 2+ cations increased the quantity of phosphonate adsorbed on the metal surface considerably. Varying the Ca/HEDP molar ratio in the solution between 0.5 and 4.0, the Ca/HEDP molar ratio on the metal surface remained under a limit close to one, corresponding to what could be expected on the basis of the results obtained by radiotracer method.

The KLL and KLM Auger spectra of 3d transition metals, Z = 23–26

Abstract High resolution (1.0–1.6 eV) X-ray excited KLL and KLM Auger spectra and the respective Auger parameters of V, Cr, Mn and Fe, obtained from thin metallic layers, are reported. The corresponding experimental (Auger) transition energies (the first high resolution experimental data except for Mn) and relative Auger intensities are compared with data obtained earlier following electron capture in the decay of radioactive isotopes, and also with available theoretical estimates. Differences in the surface chemical states of the samples and in the methods applied for evaluation of the spectra could explain the considerable deviations between the two sets of experimental results, rather than differences in the Auger process following photoionization and electron capture. The number of Auger transitions identified in the KLL spectra shows the applicability of the intermediate coupling model for these cases.

KLL Auger transitions in metallic Cu and Ni

Abstract The X-ray excited KLL Auger spectra of polycrystalline Cu and Ni films, measured with high energy resolution and presented here, show intensive satellite structures of intrinsic origin. A good agreement is between the determined relative KL 23 L 23 energies or KL 3 L 3 relative intensities and their experimental (Cu) and theoretical (free atoms) values obtained earlier. However, the deviation is significant for the absolute Auger transition energies and very large for the relative intensity of the Ni KL 2 L 2 ( 1 S 0 ) line or of the initial state shakeup satellites.

Determination of the inelastic mean free path of electrons in polyaniline samples by elastic peak electron spectroscopy

Application of x-ray photoelectron spectroscopy, Auger electron spectroscopy and electron energy loss spectroscopy for quantitative characterisation of surfaces requires knowledge of the electron inelastic mean free path and its energy dependence. Inelastic mean free path values have been determined for a wide variety of solids using theoretical and experimental methods. However, the number of published inelastic mean free path values for polymers is limited. In principle, these values for polymers can be estimated using predictive formulae such as TPP-2M and the G1 formula of Gries. An alternative method for inelastic mean free path determination in polymers is elastic peak electron spectroscopy. In the present work, the surface chemical composition of polyaniline samples (undoped and doped with palladium) was analysed quantitatively using x-ray photoelectron spectroscopy. The inelastic mean free path values were determined by elastic peak electron spectroscopy using a high-energy-resolution hemispherical analyser in the energy range 500– 5000 eV. The resulting inelastic mean free path values evaluated using Ni and Ag standards are smaller than the values resulting from the G1 predictive formula of Gries and the TPP-2M predictive formula of Tanuma et al. The discrepancies in the inelastic mean free path values are discussed extensively. Copyright

A distorted field cylindrical mirror electron analyzer II Performances and application for studying ion-atom collisions

Abstract A distorted electrostatic field tandem cylindrical mirror electron analyzer (ESA-13) has been developed based on the numerical calculation published earlier. The measured parameters have verified the calculated ones. The relative energy resolution is found to be around ΔE E = 0.3% , without pre-retardation. The spectrometer is capable of analyzing electrons in the whole angular range (0°–180°) of the scattering plane with small acceptance angle and fine angular steps (0.25°).

Solid-state effects on the satellite structure of KLL Auger spectra in Cu and Ni

Discrete variational (DV) Xa cluster molecular orbital calculations were performed for describing the energy of the Cu and Ni KLL Auger satellite lines reported recently. The results of the molecular orbital cluster approximation are in good agreement with the experimental data, thus confirming the validity of the spectator vacancy model assumed earlier. It is also shown that, in the case of Ni, accounting for screening effects of free electrons in the metal is necessary and results in good agreement with the satellite-KL 2 L 3 ( 1 D 2 ) energy separation determined experimentally.

X-ray excited KLL and KLM Auger spectra of manganese

High resolution (ΔE < 1.5 eV) manganese KLL and KLM Auger spectra, obtained by photoexcitation, are persented, and the transition energies and intensities are compared with the experimental and theoretical data published earlier. Significant disagreement can be observed between the respective experimental intensity values in the cases of the most intense lines, and large differences are found between the experimental and the available theoretical transition energy values of the main peaks. The disagreements between the experimental data can be explained rather by the different chemical states of the manganese samples investigated in the separate experiments than by the different mechanisms of the Auger processes.