Local atomic structure of zinc selenide films: EXAFS data

This paper presents the results of our study of the structural state and local atomic structure of zinc selenide films obtained by thermal evaporation in supervacuum at condensation temperatures of ?150°C, 0, and 150°C. Structure-sensitive methods such as X-ray diffraction, atomic force microscopy, and EXAFS spectroscopy were used. The parameters of the local atomic environment (interatomic distances, coordination numbers) of zinc and selenium atoms were obtained by Fourier transformation.     

A boundary-value problem for a nonlinear heat-conduction equation

Methods for the numerical solution of the boundary-value problem are comidered. One method is related to the method of successive approximations and the other employs the collocation method [1]. A relationship between the latter method and the Ritz and Galerkin methods [2] is shown. An application of the collocation method to the nonstationary problem is given. The approximate solution is represented in analytic form. A way of finding the absolute error of the approximate solution is given.     

Microstructure and magnetooptics of silicon oxide with implanted nickel nanoparticles

Metallic nickel nanoparticles of various sizes are formed in a thin near-surface layer in an amorphous SiO₂ matrix during 40-keV Ni⁺ ion implantation at a dose of (0.25−1.0) × 10¹⁷ ions/cm². The micro-structure of the irradiated layer and the crystal structure, morphology, and sizes of nickel particles formed at various irradiation doses are studied by transmission electron microscopy and electron diffraction. The magnetooptical Faraday effect and the magnetic circular dichroism in an ensemble of nickel nanoparticles are studied in the optical range. The permittivity [^(e)]\hat \varepsilon tensor components are calculated for the implanted samples using an effective medium model with allowance for the results of magnetooptical measurements. The spectral dependences of the tensor [^(e)]\hat \varepsilon components are found to be strongly different from those of a continuous metallic nickel film. These differences are related to a disperse structure of the magnetic nickel phase and to a surface plasma resonance in the metal nanoparticles.     

Reactions of 3-iodolevoglucosenone with sodium derivatives of some CH acids. Chiral cyclopropanes and stable oxetenes

3-Iodolevoglucosenone reacts with the sodium derivative of ethyl cyanoacetate at −60°C to give a tetrasubstituted cyclopropane derivative; similar reactions of the sodium derivatives of ethyl acetoacetate and acetylacetone at −60 °C afford the expected transformed Michael adducts, while at 20 °C,O,C-dialkylated products of the oxetene series are formed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp 152–156, January, 1999.     

Cleavage of the 1,6-anhydro bridge in the levoglucosenone adduct with isoprene and its derivatives

Methods of opening of the 1,6-anhydro bridge in levoglucosenone (ZnCl₂-Ac₂O), its adducts with isoprene (ZnCl₂-Ac₂O, HCl-MeOH), and hydroxy derivatives (H₃PO₄-Ac_{2 O}) were studied. Cleavage of the 1,6-anhydro bridge in anomeric acetoxy derivatives of levoglucosenone-isoprene adduct by the action of BF₃ · Et₂O-Ac₂O was accompanied by acetylation at the allylic C ⁶ position.     

SF-[2]R12: a spin-adapted explicitly correlated method applicable to arbitrary electronic states

The [2](R12) method [M. Torheyden and E. F. Valeev, J. Chem. Phys. 131, 171103 (2009)] is an explicitly correlated perturbative correction that can greatly reduce the basis set error of an arbitrary electronic structure method for which the two-electron density matrix is available. Here we present a spin-adapted variant (denoted as SF-[2](R12)) that is formulated completely in terms of spin-free quantities. A spin-free cumulant decomposition and multi-reference generalized Brillouin condition are used to avoid three-particle reduced density matrix completely. The computational complexity of SF-[2](R12) is proportional to the sixth power of the system size and is comparable to the cost of the single-reference MP2-R12 method. The SF-[2](R12) method is shown to decrease greatly the basis set error of multi-configurational wave functions.     

Influence of steric factors on the direction of reactions

Russian Journal of Organic Chemistry -     

Stability in mean square of a linear stochastic differential equation

The stability of the zero solution of a first-order linear differential equation with a random right-hand side is investigated using moment equations. Transformations of moment equations are considered. Conditions for reducing the order of the moment equations are derived.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 61, pp. 119–126, 1987.