Plasma-chemical technology of treatment of halogen-containing waste including polychlorinated biphenyls

We consider the developed plasma-chemical technology of halogen-containing substances treatment. The paper contains the experimental plant schematic and the positive results obtained after the treatment of tetrafluoromethane, ozone-damaging freon 12, polychlorinated biphenyls (PCB), the waste containing fluoride and chloride organics. The technology is proposed for industrial application.     

Symmetrical features of the structure of fullerene C20

It is shown that fullerenes C₂₀ of the $ \bar 5\bar 3 It is shown that fullerenes C₂₀ of the m symmetry can form seven types of low-symmetry species of the initial “mother” fullerene molecule by means of continuous deformation. Possible routes of formation and continuous transformations of these species are presented on the adjacency graph of structural elements of fundamental regions of fullerenes C₂₀. The approach used in this work can be applied for design of structural-geometrical models of all low-symmetry species of fullerene C₂₀. Original Russian Text ? V.M. Talanov, N.V. Fedorova, V.V. Gusarov, 2009, published in Zhurnal Obshchei Khimii, 2009, Vol. 79, No. 2, pp. 285–288.     

Estimation of a priori errors in ab initio calculations of thermochemical values for the example of the dissociation energies of the ZnO and ZnS molecules

The total energies of ZnO(¹Σ), ZnO(³Π), ZnO^?(²Σ), ZnO⁺(²Σ), ZnS(¹Σ), ZnS(³Π), ZnS^?(²Σ), and ZnS⁺(²Σ) were calculated ab initio by the CCSD(T) method with the use of atomic basis sets including 80, 84, and 93 functions for O, S, and Zn, respectively. Similar calculations were performed for the Zn atom [Zn(¹ S), Zn(³ P), Zn⁺(² S), Zn²⁺(¹ S)] and several oxygen and sulfur states [O(³ P), O^?(² S), O(¹ D), O₂(³Σ), O ₂ ^? (²Π), O₂(¹Δ), S(³ P), S^?(² S), S(¹ D), S₂(³Σ), S ₂ ^? (²Π), and S₂(¹Δ)]. The ideology of engagement groups suggested by us is considered. According to this approach, data treatment can be performed on the assumption that the errors in all the 24 results obey the normal distribution law. As a result, we obtained D _e(ZnO) = 1.70 ± 0.21 and D _e(ZnS) = 1.57 ± 0.25 eV (at a 95% confidence level).     

Correlation potentials for a multiconfigurational-based density functional theory with exact exchange

A density functional theory based on a complete active space self consistent field (CASSCF) reference function with exact exchange is discussed. It is first shown that such a theory may be formulated with a correlation potential dependent on the density function and on the active space used. Auxiliary functions, such as the on-top two-particle density, are used to define uniquely the potential for different active spaces. The paper also analyses the correlation functional for some atomic and molecular cases. Large ab initio calculations are performed to obtain accurate density functions. A correlation potential is then fitted such that the reference CASSCF function gives the same density. The correlation potential values are saved in a data base for future analysis.     

Post-Hartree-Fock methods and dynamic correlation in atoms and molecules

The methods of calculation of the matrix of the exchange-correlation interaction are considered within the framework of one post-Hartree-Fock one-electron method of investigation of the properties of many-electron systems. Such post-Hartree-Fock methods are based on two-step variational self-consistent calculations of the spin orbitals and superposition coefficients of configurations in the multiconfiguration approximation. The post-Hartree-Fock method used involves an approach related to the extended Koopmans’ theorem, which, in turn, proves to be a high-energy approximation for quantum Green’s functions. Obvious application areas of the calculations of the exchange-correlation interaction within the framework of the method proposed are the multiparticle perturbation theory, the parameterization of the energy representation as a functional of the single-particle density matrix, and the theory of Green’s functions in the multiconfiguration approximation. A relativistic generalization of the method with the aim of calculating the radiative corrections for many-electron atoms and for problems of interaction with an external field in the nonstationary Floquet theory is possible.     

Three-dimensional shape of a body of minimum drag in a hypersonic gas stream

The three-dimensional aerodynamic shape of a slender body of minimum drag is determined. The solution to the corresponding variational problem is considered in a special class of surfaces, among which there are surfaces of revolution. An approximate analytic investigation is made, and the results are given of a numerical calculation by the method of local variations. It is shown that the profile of the transverse section of the optimal body has a petal shape which becomes a circle in the midsection.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 98–103, October–December, 1981.     

Influence of component ratio in the compound (Mg,Fe)3Si2O5(OH)4 on the formation of nanotubular and platelike particles

Organically modified layered magnesium silicate was for the first time synthesized by thermal treatment of a sol of silicon dioxide, magnesium hydroxide, and hexadecyl trimethylammonium bromide, with reflux of the liquid phase. The material obtained can be used as an ultradispersed component in polymer-inorganic composites.     

Synthesis of 1,2-Bis(2-phenylethenylsulfanyl)-1-phenylethene from Phenylacetylene and Sodium Disulfide

Russian Journal of General Chemistry -