Features Of Interatomic Interactions Research Articles

Highly efficient energy and mass transfer in bcc metals by supersonic 2-crowdions

During irradiation, bombardment with energetic particles, or plasma treatment, structural transformations occur in materials, in which point defects play a very important role. Highly mobile crowdions contribute to the transfer of mass and energy in the crystal lattice. Static and slowly moving crowdions are well studied, in contrast to crowdions moving at a speed exceeding the speed of sound. Here, for the first time, dynamics of supersonic N-crowdions (N=1,2) is investigated in bcc metals (tungsten and vanadium) with the help of molecular dynamics simulations. N-crowdions are excited by imparting sufficiently high initial velocities to N neighboring atoms located in the same close-packed atomic row along this row. Both supersonic 1- and 2-crowdions carry one interstitial atom each. Modeling shows that much less energy is required to excite a 2-crowdion compared to a 1-crowdion. Energy dissipation for a 2-crowdion is much slower than for a 1-crowdion suggesting that the supersonic 2-crowdion is an efficient mass transfer mechanism in bcc metals. The distance traveled by supersonic 1- and 2-crowdions in W is much greater than that in V. The supersonic crowdion in W transforms into a moving subsonic crowdion, and in V it transforms into a standing subsonic crowdion carrying a localized high-amplitude oscillation mode. These differences can be explained by the features of interatomic interactions in W and V.

X-Ray Spectral and Theoretical Study of Electronic Structure and Features of Interatomic Interactions in Phenylaminosilanes HnSi(NHC6H5)4–n (n = 3–0)

Electronic structure and features of interatomic interactions in a series of phenylaminosilanes HnSi(NHC6H5)4–n (n = 3–0) have been studied by means of computer-based simulation (electron density functional method) in comparison with experimental (X-ray and photoelectron spectroscopy). Distributions of density of electronic states of the valence band, correlation diagrams of the energy levels, and visualizations of the isosurfaces of molecular orbitals have been obtained. Major types of interatomic electronic interactions providing the Si–NH–C6H5 bonds in tetraphenylaminosilane have been elucidated.

An X-ray spectral and theoretical study of the electronic structure and features of interatomic interactions in phenoxysilanes

The electronic structure and features of interatomic interactions providing the Si–O–C6H5 bonds in H4-nSi(OC6H5)n (n = 1–4) were studied by a combined analysis of the X-ray emission and photoelectron spectroscopic data and the results of quantum-chemical calculations. Theoretical calculations were carried out using the density functional theory. The distributions of the density of states were constructed, the correlation energy diagrams were presented, and the main types of interatomic interactions in phenoxysilanes were revealed.

Electronic structure and features of interatomic interactions in methoxysilanes H n Si(OCH3)4–n

The electronic structure and features of interatomic interactions in a series of methoxysilanes HnSi(OCH3)4–n (n = 3–0) were studied via density functional theory-based computer simulation and comparison of the simulated results with the photoelectron spectroscopic data. Calculations for the Si(OH)4, SiH4, H2O, and CH4 molecules were also performed in order to establish the laws governing the electronic structure formation of methoxysilanes. The distributions of the densities of electron states in the valence band and the correlation energy diagrams, supplemented by visualization of the molecular orbitals of the compounds, were constructed.

Chemical bonding in LaFeAsO, SrFe2As2, and LiFeAs: Basic phases of new 18–56 K superconductors

Based on FLAPW-GGA calculations, a comparative study of the features of interatomic interactions in LaFeAsO, SrFe2As2, and LiFeAs layered crystals (basic phases of new 18–56 K superconductors) is carried out.

Band structure, elastic and magnetic properties, and stability of antiperovskites MCNi3(M = Y − Ag) according to FLAPW-GGA calculations

Using the full-potential linearized augmented plane wave method (FLAPW) and the WIEN2k software package, calculations of the band structure and the elastic and magnetic properties of the ternary antiperovskite carbides MCNi3, where M = Y, Zr, ..., Ag (overall, nine compounds) are performed and the features of interatomic interactions in them are considered. Stability of these antiperovskite compounds depending on the 4d metal is discussed based on the calculated energies of formation of MCNi3 from the corresponding elements (according to the formal reaction M + C + 3Ni → MCNi3), and the conclusion is drawn that the YCNi3, ZrCNi3, and PdCNi3 antiperovskites can be synthesized. The obtained results are compared with the available data on known isostructural nickel-based carbides (antiperovskites MgCNi3, ZnCNi3).

Thermodynamics of the NI-ZR melt: Specific features of interatomic interaction and transition into an amorphous state

Nickel–zirconium alloys have a high glass-forming ability in a wide range of concentrations and constitute the basis for a variety of bulky amorphous metallic materials [1]. However, until now, there is no information on the Gibbs energy of the Ni–Zr-melt formation. This fact hampers both the analysis of thermodynamic and kinetic parameters of the transition of the Ni–Zr liquid into an amorphous state and the understanding of the reasons why such a transition easily proceeds in a number of transition metal systems.

Magnetic Susceptibility and Peculiarity of Chemical Bond in the Cd-P(As) System Compounds

Specific features of interatomic interaction of semiconductor compounds of the Cd-P(As) system derived from the analysis of experimental data and theoretical calculations of magnetic susceptibility are discussed. It is shown that the A 2 B 2 5 compounds are of predominantly covalent and A 3 2 B 2 5 of dominating ionic bond character.