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A program for quantitative evaluation of x-ray photoelectron spectra has been developed to serve as a practical tool for surface chemists. The program uses the 'classic' approach of quantification and requires as input the integrated intensities of the measured XPS lines. The usual correction methods and factors can be applied and controlled independently. All necessary basic data for calculations are integrated into the main library of the program. Besides the usual 'infinitely thick homogeneous sample' geometry model, the program is able to calculate models for layered structures, both on flat and curved surfaces. Calculation for several samples or experimental data sets can be done together. Results can be presented in several forms, such as atomic %, atomic ratio, oxide molar ratio, etc., and can be stored, printed and charted. Data can be labelled and annotated. XPS MultiQuant is equipped with a user-friendly interface, full text help system and a 'wizard' for easy set-up of calculations.

Multilayer graphene (MLGR) and its bulk analog, highly oriented pyrolytic graphite (HOPG), were treated by radio frequency activated low pressure N 2 gas plasma (at negative bias 0 - pyrrole-and triazine-type at 399.7 eV and N substituting C in graphite-like network at 400.9 eV) were determined from high-resolution N1s spectral region for all samples. Pyridine and pyrrole-triazine components increase preferentially with increasing bias. Alterations of the C1s and O1s spectra are discussed in a critical approach. The amount of reacted carbon was consistent with that required for the three different nitrogen and oxygen states, thus validating the proposed assignments.

Surfaces of iron oxide of ferrimagnetic magnetite (Fe3O4) nanoparticles (MNPs) prepared by Massart's method and their functionalized form (f-MNPs) with succinic acid, L-arginine, oxalic acid, citric acid, and glutamic acid were studied by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR-S), UV-vis, thermogravimetric analysis (TGA)/differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), and reflection electron energy loss spectroscopy (REELS). The XPS analysis of elements and their chemical states at the surface of MNPs and f-MNPs revealed differences in chemical bonding of atoms, content of carbon–oxygen groups, iron oxide forms, iron oxide magnetic properties, adsorbed molecules, surface coverage, and overlayer thickness, whereas the Auger parameters (derived from XPS and Auger spectra) and elastic and inelastic scattering probabilities of electrons on atoms and valence band electrons (derived from REELS spectra) indicated modification of surface charge redistribution, electronic, and optical properties. These modified properties of f-MNPs influenced their biological properties. The surfaces biocompatible for L929 cells showed various cytotoxicity for HeLa cells (10.8–5.3% of cell death), the highest for MNPs functionalized with oxalic acid. The samples exhibiting the largest efficiency possessed smaller surface coverage and thickness of adsorbed molecules layers, the highest content of oxygen and carbon–oxygen functionalizing groups, the highest ratio of lattice O2− and OH− to C sp2 hybridizations on MNP surface, the highest ratio of adsorbed O− and OH− to C sp2 hybridizations on adsorbed molecule layers, the closest electronic and optical properties to Fe3O4, and the lowest degree of admolecule polymerization. This high cytotoxicity was attributed to interaction of cells with a surface, where increased content of oxygen groups, adsorbed O−, and OH− may play the role of additional adsorption and catalytic sites and a large content of adsorbed molecule layers of carboxylic groups facilitating Fenton reaction kinetics leading to cell damage.

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Accurate determination of overlayer thickness on samples with curved surfaces is of growing importance, especially in connection with nanometric materials systems. In this work two simple geometries are treated; closely packed spheres, well representing powder samples, and close-packed cylinders, modelling fibrous samples. In the case of the powder samples (the arrangement is similar to the structure of the closest packed spheres) in addition to the intensity originating from curved layers of the top row of the spheres, the contribution of the partially visible spheres of the second and third rows below the top row are also considered, enhancing the accuracy of the calculations. As is shown, the method of calculation for spheres and cylinders is similar but the values of the geometry correction factors are different. The applicability of the derived geometry correction factors, based on pure geometrical considerations, is supported with experimental data obtained in two material systems: the thickness of oxide and carbonaceous contaminant layers on Si 3 N 4 powder and Al foil were determined.These types of calculations were conveniently performed by the XPS MultiQuant program providing not only the geometry correction factors but also other parameters, such as cross-sections, asymmetry parameters, etc.

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The influence of calcium and zinc ions on the corrosion inhibition effect of 1‐hydroxyethane‐1,1‐diphosphonic acid (HEDP) on carbon steel has been investigated by electrochemical techniques, X‐ray photoelectron spectroscopy, and atomic force microscopy. Addition of calcium or zinc ions greatly increased the inhibition efficiency of HEDP in a synergistic manner. The highest inhibition effect was obtained for molar ratios of Ca/HEDP = 0.5 and Zn/HEDP = 3 for 3×10−4 mol dm−3HEDP . The corrosion inhibition mechanism in the presence of these additives proved to be different from that with HEDP alone and was related to the formation of different complex species between HEDP and cation additives. The frequency response of the studied system was described by a transfer function containing two relaxation time constants corresponding to the charge‐transfer process and the porous oxide layer. Higher zinc and phosphorous content in the inhibitor layer and a continuous change in the O‒Fe and HO‒Fe ratio were achieved by increasing zinc concentration in the solution (in the range Zn/HEDP = 0.5–3) as supported by XPS measurements. Changes in the chemical structure were established in the oxide‐hydroxide layer developed spontaneously on the steel surface. The synergistic effect of inhibitor compounds appeared also in surface morphology, leading to the development of smooth, i.e., dense, protective layers as revealed by atomic force microscopy. © 1999 The Electrochemical Society. All rights reserved.