A theoretical description of reflection of hydrogen isotopes from a solid body based on data available in modern literature on the cross sections for elastic and inelastic scattering of ions is presented. The results of the analytical calculation are compared with the results of computer simulation and experimental data. The interaction of hydrogen isotopes with energies from 300 eV to 25 keV with materials in a wide range of atomic numbers, namely Be, C, Ti, Ni, W, Au, is considered. A critical review of existing analytical models of multiple scattering of light ions in solids is performed.

We considered the experiments, in which longitudinal electromagnetic oscillations are excited by electron (Reflected Electron Energy Loss Spectrometry or REELS) and X-ray (X-ray Photo Electron Spectroscopy or XPS) scanning of solids. Peaks in the spectra of electron energy losses associated with the excitation of plasma oscillations of free (valence) electrons of a solid body were found. We considered (e, 2e) the experimental analysis of secondary electron energy spectra showing peaks corresponding to the energy of plasma oscillations (Langmuir waves). We also studied the electron bombardment-induced photon emission experiments in the energy range coinciding with the energy of plasmon excitations; we observed the energy of plasmon excitations. We noted that the introduction of the “plasmon vacuum” concept provided a consistent quantum-mechanical definition of plasmon relaxation by the emission of longitudinal photons. We identified the wavelength range in which the most intense emission of longitudinal quanta is observed.

An analytical theory of the reflection of light ions from solids is presented. The theory is based on the method of solving the elastic scattering problem (the Oswald–Kasper–Gauckler method), successfully tested in the theory of electron scattering. The solution of a boundary value problem for light ion reflection from solids based on the invariant imbedding method is constructed. Particle interaction with amorphous and polycrystalline samples is considered. Analytical formulas for calculating the integral reflection coefficients of particles and energy are obtained. It is shown that an analytical solution can be obtained only within the framework of a small-angle approximation. The obtained analytical solutions are based on the path length distribution function taking into account the maximum residual range. It is demonstrated that within the framework of the analytical theory the reflection coefficients are determined by two dimensionless parameters: the ratio of the residual range to the transport path length and the screening parameter. The results of theoretical consideration are compared with the data of computer simulation. Numerical calculations are performed for the case of reflection of protons with initial energy E0 = 1–10 keV from Be, C, Cu, and W targets for different scattering geometries. The results of the calculated integral reflection coefficients of particles and energy show satisfactory agreement between analytics and computer simulation.

An analytical solution to the equation for the distribution of the flux density of reflected light ions over the path length and energy losses in the target is obtained. It is based on the solution of boundary problems for the transport equation using the invariant imbedding method in the small-angle approximation. In the case of proton reflection from copper and tungsten targets, the analytical results are compared with computer-simulation data obtained using the OKSANA program, as well as with experimental data. The possibility of verifying the stopping power of the target material based on the created methodology is noted.

X-ray photoelectron emission spectra of thermally reduced graphene oxide samples and carbon nanotubes (CNTs) with various oxidation degrees are presented in this paper. A method for the reconstruction of differential electron inelastic scattering cross sections from the energy loss spectra of photoelectrons is described and discussed. The analysis of the part of the characteristic photoelectron energy loss spectrum adjacent to the C1 peak indicated a considerable influence of the thermal reduction of graphene oxide on the electron properties of the samples obtained. On the contrary, the oxidation of CNTs by refluxing in a concentrated HNO3 solution does not change the free electron excitation spectrum.

The effect of a metal that weakly forms carbides, i.e., aluminum, on the phase composition, structure, and electrophysical properties of amorphous diamond-like silicon-carbon films is studied. The obtained results are compared with the influence of carbide-forming transition metals, titanium and hafnium, on the same characteristics. It is shown that the effect of aluminum and transition metals on the structure and properties of silicon–carbon films is fundamentally different. The introduction of aluminum in a wide range of concentrations, in contrast to transition metals, does not lead to the formation of a nanocrystalline phase in the films. The concentration dependences of the electrical conductivity upon the introduction of aluminum have a smooth, monotonic character, but upon the introduction of transition metals, they have a pronounced percolation character, and the absolute values of changes in the electrical conductivity differ by orders of magnitude. The set of studies carried out makes it possible to conclude that the reason for these differences is the interaction of the introduced metals with different chemical elements of the film. Transition-metal atoms interact mainly with carbon atoms to form highly conductive carbide nanocrystals. In contrast, aluminum atoms mainly interact with oxygen atoms and form an amorphous phase of aluminum oxide.

Samples of single-crystal silicon coated with gold nanolayers are investigated. The samples are obtained by two methods, namely, gold sputtering using a Xe + beam with an initial energy of 7 keV and the method of thermal deposition. The preliminary analysis of samples based on deciphering the energy spectra of reflected protons with an initial energy of 25 keV is performed. By the methods of angle-resolved X-ray photoelectron spectroscopy (ARXPS), the thicknesses of the gold coatings on silicon are determined. Analysis of the samples using X-ray photoelectron spectroscopy is performed by comparing the intensities of the Au 4 f and Si 2 p maxima measured at different angles of photoelectron detection. The calculations carried out by traditional methods indicate a marked dependence of the calculated gold-coating thickness on the angle of sight for the case of single-layer- and subsingle-layer coatings. It is shown that such a discrepancy is possible if gold is deposited onto silicon in the form of clusters forming islands rather than in the form of a continuous homogeneous coating. The possibility of gold islands moving relative to silicon in upper silicon layers subjected to proton bombardment at grazing angles to the surface is discussed.

A quantitative method for interpreting the spectroscopy signal of elastically reflected electron peaks is constructed taking into account the layer-by-layer analysis of the content of hydrogen isotopes in structural materials used in the international experimental thermonuclear reactor ITER under construction. The relative protium and deuterium concentrations in hydrocarbon samples are determined. The relative deuterium concentrations in a beryllium sample are determined.

A solution to the boundary problem for describing the formation of peaks of electrons elastically reflected from multicomponent samples is presented. It is shown that the problem leads to Lyapunov-type equations and allows the construction of an effective numerical solution. A small-angle theory for the elastic reflection of electrons from multicomponent materials is developed, which makes it possible to obtain analytical solutions that describe the intensity of the peaks of electrons reflected from various target components. A method is developed for interpreting and quantitatively processing the peaks of elastically reflected electrons, taking into account multiple scattering effects.

A small-angle theory is developed for the elastic reflection of electrons off multicomponent materials. A way of interpreting signals of elastic peak electron spectroscopy (EPES) is devised that considers the multiple scattering effect. It is shown that a straight line approximation describes the EPES signal with acceptable accuracy.

The paper considers the application of the traditional X-ray photoelectron spectroscopy (XPS) methodology: the Overlayer Thickness Determination for the analysis of coating parameters. In particular situations considered in this work, it is energetically favorable for the atoms of the coating to form clusters, but not be evenly distributed on the surface of the substrate material. The change in the XPS signal is analyzed in situations when the coating is not a plane-parallel homogeneous layer, but an island (cluster) structure. The mathematical model of the XPS signal formation is considered for the case of the cluster covering in the form of parallelepipeds. Photoelectron path distributions (in the coating material) analysis indicated a strong dependence of the signal on the viewing angle. For the purpose of analysis, experimental spectra were obtained for several samples: gold depositions of various thicknesses on a silicon substrate. The spectra were measured for different viewing angles of photoelectrons and interpreted within the Straight Line Approximation (SLA). It is shown that proposed simplest model of an island coating allows to describe the effect of a decrease in the value of the effective average coating thickness, determined in plane-parallel geometry, with an increase in the viewing angle, observed in XPS experiments with angular resolution.

Analytical solution for the reflected light ions Pass Length Distribution Function (PLDF) equation is obtained. Reflected ions energy spectra calculated on the basis of the developed method shows satisfactory agreement with experimental data. The effectiveness of the developed methodology in the procedure for verifying the stopping power value is indicated.

A method of layer thickness determination by X-ray photoelectron spectroscopy (XPS) is analyzed. Angle-resolved XPS spectra measured for three samples (gold films of different thicknesses located on top of silicon substrates) have been interpreted by the straight line approximation (SLA) model. Two configurations of films were considered: (i) a flat surface of a semi-infinite layer (substrate) is covered with a flat homogeneous layer, (ii) coating constitutes an island (cluster) structure. It is shown that the simplest model of an island coating makes it possible to qualitatively explain the effect of decreasing of the effective average coating thickness observed in the angle-resolved XPS experiments.

Samples of thermally reduced graphene oxide are studied using differential cross sections for photoelectron inelastic energy losses. We compare different procedures for recovering cross sections from the photoelectron energy spectra resulting from multiple inelastic scattering. It is shown that the cross section for inelastic energy losses (which uniquely characterizes allotropes of carbon) in the sample containing the minimal amount of carbon oxides corresponds the best to pyrolytic graphite.

The dynamics of X-ray photoelectron emission spectra is studied in the region of the 1s carbon line with increasing treatment temperature for graphene-oxide samples. It is established that, as the degree of oxide reduction increases, the role of the mechanism related to energy losses for the excitation of π-plasmon oscillations produced in the presence of sp2 bonds in the carbon sample increases. Spectral analysis shows that the π-plasmon peak is manifested in the spectra of samples annealed at temperatures exceeding 200°C. When determining the differential cross sections for inelastic electron scattering, the difference between the energy losses in the surface sample layers and the homogeneous bulk located far from the surface is taken into account. The obtained spectra are compared with those of multilayer graphene and pyrolytic graphite. It is shown that the analysis of graphene oxide using X-ray photoelectron spectroscopy gives a picture on a nanometer scale. The obtained data can differ noticeably from the Raman spectroscopy data corresponding to the millimeter scale.

The possibility of measuring hydrogen depth profiles by means of electron spectroscopy is demonstrated. In the near-surface layer with a thickness corresponding to the inelastic mean free path (IMFP) the elastic peak electron spectroscopy (EPES) is employed for this purpose. For measuring hydrogen isotope depth profiles deeper in the solid at depths corresponding to the transport mean free path (which is by several orders of magnitude larger than the IMFP) the so-called spectroscopy of reflected electrons (SRE) is used. In this work, the SRE technique is employed for the investigation of a pure beryllium sample and a beryllium sample implanted with deuterium atoms.

A method for extracting the differential inelastic scattering cross sections of electrons xin(Δ) from the energy spectra of electron spectroscopy is developed. The derived cross sections are verified by interpreting experimental data on electron-energy-loss spectra, X-ray photoelectron spectroscopy, and Auger spectroscopy. The paper highlights existing methods for determining the cross sections xin(Δ) using electron-energy-loss spectra. Inconsistency in analytical solution of the inverse problem (i.e., deconvolution) is shown for calculating the inelastic scattering cross section of electrons xin(Δ). In this paper, the solution of the mathematically ill-posed problem of cross-section retrieval is based on a fitting procedure consisting in multiple direct-problem calculations, i.e., calculations of the electron spectra taking into account both elastic and inelastic multiple scattering events. To implement an efficient fitting algorithm, a high-performance procedure for solving the direct problem of determining the energy spectra of electron spectroscopy is developed. The method for calculating the spectra is based on solution of the boundary problem for the transport equation by using the invariant imbedding method. The procedure developed in this work allows the energy-loss cross sections in the surface layer and in the sample homogeneous bulk layer remote from the surface to be reconstructed. The cross sections xin(Δ) retrieved from experimental data on the electron-energy-loss spectra satisfactorily reproduce the Auger spectroscopy and X-ray photoelectron spectroscopy signals and vice versa: the cross sections xin(Δ) retrieved from the X-ray photoelectron spectroscopy data satisfactorily reproduce the electron-energy loss and Auger spectroscopy spectra. It is shown that for the description of the X-ray photoelectron spectroscopy spectra of Be, Mg, Al, Nb, and W, it is not necessary to use additional mechanisms of energy losses, so-called “intrinsic excitations”.

New quantitative method of hydrogen isotopes detection in engineering materials used for fusion is introduced. The study proposes a theory of small-angle atomic particle elastic reflection from multicomponent materials. A method for interpreting Elastic Peak Electron Spectroscopy signals considering the multiple scattering effect was developed. It is shown that ignoring the multiple scattering effect results in significant errors with quantitative evaluation of Elastic Peak Electron Spectroscopy signals.