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Interaction potentials were obtained by the density functional theory (DFT) and nuclear stopping powers (NSP) were calculated for 48 systems in the energy range above 10 eV. It was shown that NSP calculated using the DFT potentials in the collision energy range of 10–1000 eV give more accurate values comparing with the SRIM data, obtained data differs from SRIM data by 15–70%. The presence of a potential well leads to the emergence of an additional NSP peak at low energies. Comparison of classical calculations of the transport cross section with semiclassical ones showed their identity at energies of up to 1 eV. The criterion for the applicability of classical calculations for the transport cross section and NSP cross sections is the condition l>1 (l is the angular momentum). The importance of including multichannel scattering in NSP calculations was demonstrated, for the case of energies below 20 eV.

A universal dependence (scaling) is proposed for estimating the cross sections for the production of K-vacancies in collisions of keV ions and atoms. The scaling is based on the studies of the spectra of inelastic losses, emission cross sections of characteristic Auger electrons, and radiation in the decay of K-vacancies. A formula is suggested for collisions of atoms with $$Z > 10$$ , which explains the ionization of the K-shell by the transitions due to the superpromotion of terms. The scaling phenomenon makes it possible to estimate the cross sections for the production of K-vacancies for as yet unexplored cases of atomic collisions and to approximately find in this way possible electron stopping powers in passage of ions through a solid body. It can also be used to determine the composition of matter under ion irradiation.

The electronic stopping losses for p–He and p–Ar systems are compared with independent measurements of cross sections for elementary processes. It is shown that quantitative agreement can be reached if the fact that significant energy losses are carried away by knocked-out electrons is taken into account. The dependence of the average energy of knocked-out electrons on the impact velocity for velocities that are smaller than 1.5 a.u. can be described within the framework of dynamic ionization theory. It is established that the equilibrium charge of beam particles depends on the ratio of the stripping and charge-exchange cross sections, and the use of frequently applied universal models for description of the equilibrium charge in the case under consideration is not justified. It is shown that the contribution of excitation processes for the studied cases does not exceed 7–12%, which differs from traditional concepts of equality between the contributions of ionization and excitation processes. The inclusion of multiple ionization processes, which increases the electronic stopping power by 6% in the case of p–He and by 23% in the case of p–Ar, turns out to be important.

The exponential component of the electron spectrum during Ne–Ne collisions is shown to be associated with the electron transitions from the autoionization term to the continuum. The characteristics of this term have been determined. The exponential shape of the spectrum is explained by the absence of interference between the transition amplitudes as the particles come close together and fly apart due to a high transition probability. For Auger transitions in the quasi-molecule we have determined the dependence of the mean Auger transition energy on the reached internuclear distance, which agrees well with the results of energy level calculations for the Ne–Ne system, and the dependence of the weighted mean Auger transition probability on the observed electron energy Ee. We show that the transition probability decreases significantly with increasing Ee as the internuclear distance decreases, apparently, due to a decrease in the overlap integrals of the wave functions for the interacting electrons. Our analysis allows a coherent picture of ionization in collisions of intermediate-mass ions with keV energies to be formed.

It is shown that the excitation of autoionization states during the collisions of keV-energy ions with a solid plays a determining role in the formation of inelastic energy losses and, accordingly, the electronic-stopping cross section Se. It is proposed to estimate the Se values using the relationship between the cross section for autoionization-state excitation and the ionization cross section. For cases where the ionization cross sections are unknown, scaling is used to calculate the ionization cross sections when the L and M shells are excited. The threshold dependence of Se versus the energy of bombarding ions is predicted.

The reflection coefficients were calculated for the scattering of hydrogen isotopes and helium atoms from the surface of amorphous beryllium, carbon, and tungsten targets, which are of interest in the physics of thermonuclear plasma. The results demonstrate good agreement with the available experimental data. The isotope effect in the reflection of particles from the wall was analyzed. For the reflection of He atoms, a similarity in reflection coefficient versus Lindhard parameter curves was observed.

A model for estimating the contribution of autoionization state formation to inelastic energy losses in collisions of keV-energy ions with solids is proposed. Using the suggested scaling for L and M shell excitation it is possible to estimate the ionization cross sections and the contribution of the ionization processes to the electronic stopping power dE/dx. The model predicts a threshold behavior of dE/dx. In the cases studied the formation of autoionization states gives important contribution to the value of dE/dx.

We have obtained the range distributions for H, D, and He atoms within an energy range of 0.1–100 keV in amorphous W and Si for the normal incidence of bombarding particles. Calculations have been performed both in the binary collision approximation and by a more accurate method of calculating particle trajectories. It is shown that the results of both methods are in good agreement with each other and with experimental data on the mean ranges for the H–Si system. The influence of the attracting well in the particle–solid interaction potential on the results of calculations is estimated.

Particle reflection coefficients for scattering of hydrogen and deuterium atoms from amorphous beryllium, carbon and tungsten were obtained, which are of interest for thermonuclear reactor physics. For the case of deuterium scattering from tungsten the data were also calculated for polycrystalline and crystalline target. The calculations were carried out by two methods: by modeling the trajectories of the incident particles and by using the binary collision approximation. Interaction potentials between hydrogen and helium atoms and the selected materials were calculated in the scope of the density function theory using program DMol for choosing wave functions. The dependence of the reflection coefficient RN on the potential well depth was found. The results demonstrate a good agreement with the available experimental values.

A simple formula for estimating the screening constant has been proposed. This formula fits well experimental data on the interaction potentials. Quantitative description of the experiment for the effect of electronic screening on the nuclear synthesis reaction cross-section for the D+-D system has been obtained. A conclusion has been made that the differences between the measured cross-sections and their theoretically predicted values, which take place in more complicated cases nuclear synthesis reactions, are not caused by uncertainties in the knowledge of potentials.

Computer simulation of rainbow and “ion focusing” effects taking place in scattering of Ar atoms on Al(1 1 1) and Ag(1 1 1) crystal surfaces have been performed. The trajectory calculation and vector summation of forces of the projectile atom interaction with crystal atoms have been shown to provide good fitting of the available experimental data. The thermal vibration amplitude for atoms located on the surface of crystals under study has been determined. A functional form of the potential has been proposed that fits well the experimental data.

Reflection coefficients and angular distributions of scattered particles in bombarding various practically applicable targets with H, D and Ar atoms have been calculated in a wide range of incident angles and energies. In the case of glancing angles and crystalline targets, the reflection coefficient of almost 100% has been observed. This effect should be taken into account in calculating energy input into the divertor material and in designing protective screens for spacecrafts.

Multiple scattering at grazing angles of incidence is shown to affect the value of inelastic energy loss determined from the position of the quasi-single scattering peak on the energy scale.

Beryllium fluxes into the ITER tokamak plasma due to sputtering of the first wall by D and T atoms leaving the plasma were estimated. The energy spectra of deuterium and tritium atoms leaving the plasma were modeled using the DOUBLE-MC code. The flux of beryllium atoms entering the plasma was estimated to be 6.5 × 1017 atoms s−1 m−2. Azimuthal anisotropy of the fluxes of atoms leaving the plasma was taken into account, which increased the estimate of the beryllium flux by 15% compared to that in the isotropic case. With the typical ITER plasma confinement times of 3–5 s, this means that the concentration of beryllium impurities can be 2.5%–4.2% of the mean ion plasma density. Such a high content of beryllium ions in the region close to the separatrix can lead to significant sputtering of the divertor with multiply charged beryllium ions. The proposed model allows estimation of the flux of sputtered tungsten atoms into the near divertor plasma. By varying the density of the gas-plasma target and the electron temperature on the separatrix, one can reduce the tungsten impurities influx into the plasma.

The paper suggests a scaling for calculating cross-sections of L-vacancy formation due to atomic collisions in the keV range of collision energies. A technique for estimating the probability of inelastic transition by differentiating its cross-section dependence on the collision energy is also proposed.

Values of He+–Au potential at small internuclear distances (R = 10−4 to 10−3 nm) have been obtained from the Rutherford backscattering (RBS) data. The potential has been shown to be independent of the collision velocity and close to the potential approximation proposed in Zinoviev (2011) [1]. Experimental data on the electron screening of the Coulomb potential enabled calculation of corrections for the nuclear fusion cross-sections and improvement of the RBS data quantitative analysis.

The paper presents a model for calculating atom scattering from a polycrystalline target and results of energy spectra measurements of Аr + ions scattered from Al and Ge surfaces. It has been shown that allowance for multiple scattering at glancing angles α = 8 ÷ 22° affects the magnitude of inelastic energy loss determined from the position of the single scattering peak. A formula describing the inelastic energy loss dependence on the distance of closest approach of colliding atoms has been proposed. It has been shown that the comparison of experimental and calculated peak/background ratios in energy spectra for scattering from both the polycrystalline and amorphous targets allows us to estimate the surface structure.

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The interatomic potential determines the nuclear stopping power in materials. Most ion irradiation simulation models are based on the universal-Ziegler-Biersack-Littmark (ZBL) potential (Ziegler et a1.,1983), which, however, is an average and hence may not describe the stopping of all ion-material combinations well. Here we consider pair-specific interatomic potentials determined experimentally and by density functional theory simulations with DMol approach (DMol software, 1997) to choose basic wave functions. The interatomic potentials calculated using the DMol approach demonstrate an unexpectedly good agreement with experimental data. Differences are mainly observed for heavy atom systems, which suggests they can be improved by extending a basis set and more accurately considering the relativistic effects. Experimental data prove that the approach of determining interatomic potentials from quasielastic scattering can be successfully used for modeling collision cascades in ion-solids collisions. The data obtained clearly indicate that the use of any universal potential is limited to internuclear distances R

When an ion arrives at the metal surface, it produces an induced charge that affects formation of the ion–metal system electron states. The state promotion in a dipole field is discussed and measured electron energy spectra produced in multiply ion–metal collisions are explained using this model. The paper presents the results of calculating the electron density distribution of induced charge near the metal surface in the classical approach and also, quantum mechanically, with a variation model of a Density Functional Theory approximation. In the both cases the spatial cloud of induced charge is oblate parallel to the metal surface; in quantum mechanical solution the cloud is also shifted towards the approaching ion.

The increase in nuclear fusion reaction yields relative to the theoretically predictions was observed in collisions of deuterium ions at energies below 10 keV with a number of metals presaturated with deuterium. In this paper, this effect is explained by focusing of trajectories during ion channeling in metal microcrystals.

Accurate potential data for system Ar + , С + , Cd + , Kr + , Ne + , Xe + , Zn + –Xe, Ar + –Ar and Ne + –Ne were obtained by analyzing the scattering cross-sections. These data extend the existing database of potentials obtained experimentally. To fit better the existing data, a new analytical form of the potential is proposed. The fitting errors analysis shows that the universal potential can be used only for the systems with nuclear charges Z > 18 and in the region where the distances of closest approach are less than R a f (here a f is the Firsov screening length (see below)). The model of individual potentials is suggested, which extends the region of potential application and minimizes the fitting errors.

We have performed a theoretical investigation of the possibility of laser action on the innershell 0–1 (2s–2p) transition of Ne-like ions. The plasma conditions for the effective lasing are found. Here we present atomic-kinetic calculations for gain values along the Ne-like sequence; the regularities along the sequence are drawn. These data are important for the experimental observations of X-ray laser effects.

When a multiply charged ion with charge Z approaches the metal surface, a dipole is formed by the multiply charged ion and the charge induced in the metal. The states for such a dipole are promoted into continuum with decreasing ion–surface distance and cross the states formed from metal atom. The model proposed explains the dominant population of deep bound states in collisions considered.

The probability of single-photon decay of highly excited double hole state of atoms is considered. The concrete calculations are performed in the lowest order of perturbation theory in interelectron interaction for states (2s)-2 in Ne, (2s)-2 and (2p)-2 in double ionized Ar−Ar++ and (4d)-2 in Xe.