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We present the most informative results of archeological and geophysical field studies of the Baraba forest-steppe over the last three years. The studies were carried out for archeological sites of different types belonging to a wide time interval (~6000 BC-2000 AD). Data on the presence, size, and configuration of archeologic objects were obtained by magnetometry and electrometry. We studied contrast between the magnetic properties of the upper horizon of present-day soil and underlying substratum at archeologic sites of different types and ages. Low contrast reduces the amplitudes of magnetic anomalies above buried ancient structures. It is shown that geoelectric methods are efficient in cases when magnetometry is not.

The secular variation rate (SVR) of geomagnetic-field components (horizontal intensity H , vertical intensity Z , and inclination I) shows two types of fluctuations: with a short period (3 ± 0.15 years) and a long period (10-70 years). The amplitudes of the short-period fluctuations (SPFs) were estimated. The SPFs are uniform throughout the Earth, the Z and I SVR fluctuations are synchronous and have the same phases, and H SVR fluctuations are opposite in phase. Modeling of an eccentric-dipole field with a variable axial-pole latitude has shown that the SPFs in SVR are caused by the nutation of the dipole axis (and by the outer-core current systems responsible for the dipole field). Long-period fluctuations (LPFs) in SVR manifest themselves differently in different regions, and their nature is dominated by the effect of currents in the liquid core near the mantle.

An ungrounded horizontal loop, a common transmitter type in TEM surveys, makes up a system with distributed parameters with the earth under it. It can be simulated by an equivalent circuit with lumped parameters at late times and/or low frequencies, but at early times commensurate with the period of free current oscillations, the lumped circuit model fails to account for experimental data. At high frequencies and/or early times, the wire, in combination with the underlying earth, forms a transmission line in which current behaves according to the wave equation. This model allows calculating the current at any time and at any loop point with reference to the theory of long transmission lines. At early times, the loop self-responses depend on near-surface resistivity and environment and its primary magnetic field differs from that predicted by the classical theory of TEM surveys. Therefore, inversion of early-time response in terms of the conventional TEM system model is meaningless. However, as illustrated with a loop shunted by a matching resistor, the loop model as a combination of two transmission lines enables the inversion of the early-time current response in terms of the line parameters and near-surface resistivity.

Within density functional theory with regard to the dispersion interaction the crystal structure parameters of hydrogen azide are determined. The pressure effect on its structural and electronic properties is studied in the range of 0-10 GPa. By means of the Vinet equation of state the bulk modulus of compression is found to be 9.26 GPa. It is shown that with an increase in the pressure molecules approach each other in molecular layers and this is accompanied by an increase in the total electron density contours, which means the principal possibility for polymerization. The external pressure of 10 GPa leads to the broadening of the upper valence energy bands and a decrease in the band gap from 6.14 eV to 5.51 eV.

Three possible models of the ordered arrangement of B, C, and N atoms in chalcopyrite sublattices are considered. Crystal lattice parameters are obtained from the first principles, band spectra are calculated, and the role of B, C, and N atoms in the formation of chemical bonds and the valence band in the B₂CN, BC₂N, and BCN₂ crystals is revealed.

Electronic characteristics of trHbN hemoglobin whose composition contains the (ONOO) group with the structure close to the structure of 1) peroxynitrite and 2) a nitrate anion in the gas phase are calculated. Electron correlation is considered by the multiconfigurational self-consistent field (MCSCF) method during the optimization of the geometry of the whole structure. Localized molecular orbitals (MOs) are used as starting ones. In the wave function of the MCSCF method two complete active subspaces (CASs) are set. These are the subspace of iron atom 3 d orbitals and the subspace describing chemical bonds in peroxynitrite (bonding and antibonding MOs plus the orbital of one lone pair on the O₂ moiety. The composition of the system involves two water molecules. The peroxynitrite structure is considered in two different spin states that correspond to the singlet and triplet states of this anion in the gas phase where the vibrational spectrum is characterized by frequencies of about (70-30) cm^-1. The protective reaction of the active center of the tubercule bacillus is discussed.

The geometric parameters of the molecular structures of 4-monoiododipyrrine, 4,4′- and 5,5′-dibromodipyrrine complexes with zinc(II) and boron(III) of the composition [ZnL₂] and [BF₂L] respectively are determined at the M06 and B3LYP levels of density functional theory with the Def2-SVP basis set. The lengths of Zn-N, B-N, and B-F coordination bonds, N-X-N, F-B-F, C-C-C bond angles, the dihedral angles between the planes of pyrrole rings in the dipyrrine ligand, dipyrrine planes in [ZnL₂], dipyrrine core and the plane passing through the atoms of the BF₂ group are optimized. The effect of structural factors on the geometric parameters and the widths of the HOMO-LUMO energy gap in halogen substituted dipyrrinates is analyzed.

The geometrical structures, relative electronic and magnetic properties of small Al _n Co^- (1 £ n £ 9) clusters are systematically investigated within the framework of density functional theory at the BPW91 level. The single Co doping can dramatically affect the ground state geometries of the clusters. At the same time, the resulting geometries show that the lowest energy Al _n Co^- clusters prefer to be three dimensional structures. Here, the relative stabilities are investigated in terms of the calculated average binding energies, fragmentation energies, and second-order energy differences. Moreover, the result of the highest occupied-lowest unoccupied molecular orbital energy gaps indicates that Al₆Co^- clusters have the highest chemical stability for Al _n Co^- (1 £ n £ 9) clusters. Furthermore, the natural population analysis reveals that the charges in Al _n Co^- clusters transfer from the Al frames to the Co atom. Additionally, the analyses of the local and total magnetic moments of the Al _n Co^- clusters show that the magnetic effect mainly comes from the Co atom.

The reaction mechanism of the N-N bond cleavage in Ta(IV) hydrazido and hydrazidium complexes is studied using density functional theory. The N-N bond cleavage in Ta(IV) hydrazidium generates formal Ta(IV) nitridyl. The N-N bond cleavage in Ta(V) hydrazido gives terminal Ta(V) nitrido species. In the tetrahydrofuran solvent, terminal Ta(V) nitrido dimerizes through a one-step direct pathway leading to the [Ta(V),Ta(V)] bis(m-nitrido) product. Two Ta-N bonds form simultaneously between the Ta center of one molecule and the terminal N atom of another. In the toluene solvent, there are two pathways of H atom abstraction and protonation producing mononuclear Ta(V) parent imide. The former consists of three steps originated from formal Ta(IV) nitridyl. The latter is unfavorable with terminal Ta(V) nitrido as the precursor.

We present density functional calculations of O₂ and CO adsorption on an AlAu₆ cluster. It is found that in the AlAu₆ cluster the active sites would be first occupied by coming O₂ rather than CO due to a more negative binding energy of the former. Furthermore, the catalytic mechanisms of CO oxidation in AlAu₆ clusters, which are based on a single CO molecule and double CO molecules, are discussed. This investigation reveals that the reaction of a single CO molecule with the AlAu₆O₂ complex has the lowest activation barrier (0.27 eV), which is 0.51 eV lower than that of the pure cluster. For the AlAu₆O₂(CO)₂ complex, due to the structural distortion of the AlAu₆ cluster, the activation barrier of the determination rate is higher by 0.53 eV than that of the AlAu₆O₂CO complex, which shows that the cooperation effect of the second CO molecule can go against CO oxidation. For the Al@Au₆O₂(CO)₂ complex, the activation barrier of the determination rate is lower by 0.07 eV than the path of one CO molecule, which demonstrates that the cooperation effect of the second CO molecule can prompt CO oxidation.