A structural study of CN treated amorphous silicon

Recently, a remarkable technique to overcome the problem of light-induced degradation in amorphous silicon (a-Si) solar cells using a cyanide (CN) treatment has been developed. Structural and bonding characteristics of CN in a-Si has been studied using ab initio molecular dynamics simulations. It was found that CN incorporation results in more than just the termination of dangling bonds. The connectivity of the covalent random network increases because the CN changes from triply bonded, which is a common form in molecular CN, to the singly bonded form. This may be the mechanism by which CN incorporation produces significant reductions in light-induced degradation.     

Oscillator strength of a two-dimensional D ion in magnetic fields

In the present paper we determine the oscillator strength of two-dimensional (2D) D⁻ ions under the influence of a static magnetic field. The results are important for the analysis of the optical transitions observed in semiconductor quantum wells. We have applied the ab initio procedure Hyperspherical Adiabatic Approach, based on the use of hyperspherical coordinates. This approach uses an adiabatic separation of the total wave function that allows accurate energies determination from molecular-like potential curves. The convergence is obtained in a systematic way by the inclusion of non-adiabatic couplings without the need of adjustable parameters.     

On the electronic band structure of zigzag-type single-walled carbon nanotubes

The electronic band structure of a zigzag-type carbon nanotube has been computed by using the tight-binding approximation method in the framework of SSH Model Hamiltonian modified by the inclusion of two Lagrange multipliers instead of one. This modification yielded an electronic band structure consistent with the experimental reports that an infinite (3,0) zigzag-type single-walled carbon nanotubes displays a metallic behaviour.     

Collisional line shifting and broadening in the fundamental P-branch of CO in Ar between 214 and 324 K

The collisional shifts and widths of several P-branch spectral lines in the fundamental band of CO-Ar have been measured at temperatures between 214 and 324 K and pressures between 0.025 and 1 atm. The widths have been determined using a line shape model based on the solution of the transport/relaxation equation for the appropriate off-diagonal element of the density matrix. The model uses a realistic molecular potential energy surface to calculate the speed dependence of the collisional broadening, and a rigid sphere potential to calculate the translational motion. It is found that both the shifting and broadening coefficients follow a power law dependence on the temperature. Additionally, it is demonstrated that studies have tended to overestimate the accuracy of collisional widths when the line shape model used to obtain the widths involves multiple fitted line shape parameters or fails to fit the measured spectra within the experimental noise.     

Cooling,identification and spectroscopy of super-heavy element ions

We briefly discuss some possibilities for cooling, identification and spectroscopy of super-heavy element (SHE) ions based on recent results obtained from studies of atomic and molecular ions in linear rf traps. Since these investigations only relied on the charge and the mass of the ion of interest, we believe it should be straight forward to adopt most of the techniques for SHE ion research.     

A three-phase single sheet tester with digital control of flux loci based on the contraction mapping principle

Tight control of flux loci in 2D testing of soft magnetic laminations is realized by a method based on the principle of contraction mapping. It is implemented through digital control of the currents supplying a three-phase yoke magnetizer and the use of circular samples. Faithful realization of the prescribed loci and good measuring accuracy are demonstrated in grain-oriented and non-oriented Fe–Si laminations.     

An investigation of finite-size scaling for systems with long-range interaction: The spherical model

A method is suggested for the derivation of finite-size corrections in the thermodynamic functions of systems with pair interaction potential decaying at large distancesr asr ^{–d –w1v3746m425nt/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">} , whered is the space dimensionality andw1v3746m425nt/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">>0. It allows for a unified treatment of short-range (w1v3746m425nt/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">=2) and long-range (w1v3746m425nt/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0"><2) interaction. The asymptotic analysis is illustrated by the mean spherical model of general geometryL ^{d–dw1v3746m425nt/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">}×w1v3746m425nt/xxlarge8734.gif" alt="infin" align="MIDDLE" BORDER="0"> ^{dw1v3746m425nt/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">} subject to periodic boundary conditions. The Fisher-Privman equation of state is generalized to arbitrary real values ofdw1v3746m425nt/xxlarge10878.gif" alt="ges" align="MIDDLE" BORDER="0">w1v3746m425nt/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">, 0w1v3746m425nt/xxlarge10877.gif" alt="les" align="MIDDLE" BORDER="0">dw1v3746m425nt/xxlarge8242.gif" alt="prime" align="BASELINE" BORDER="0">w1v3746m425nt/xxlarge10877.gif" alt="les" align="MIDDLE" BORDER="0">w1v3746m425nt/xxlarge963.gif" alt="sgr" align="BASELINE" BORDER="0">. It is shown that thew1v3746m425nt/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0">-expansion may be used to study the breakdown of standard finite-size scaling at the borderline dimensionalities.     

Evidence for the poisson distribution for quasi-energies in the quantum kicked-rotator model

A transformation on the two-dimensional torus which is related to the problem of limit distribution for the distance between the levels in the kicked-rotator model is considered. The first four moments of the r.w. which describe the numbers of visits of a point in a rectangle of measure w/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0"> are calculated. It is shown that when w/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0">w/xxlarge8594.gif" alt="rarr" align="BASELINE" BORDER="0">0 they converge to the first four moments of a Poisson r.w.     

A novel method for synthesizing diorganylphosphinous acids from red phosphorus and arylalkenes

The reaction of styrene and w176/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-methylstyrene with P in aprotic polar solvents in the presence of KOH affords diorganylphosphinous acids.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1680–1681, September, 1994.     

An unusual new reaction of α-olefins with magnesiumn-alkyl derivatives catalyzed by Cp2ZrCl2

The reaction of organomagnesium compounds (OMC) containing alkyl radicals of normal structure with w7/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-olefins, resulting in the formation of alkenylorganomagnesium compounds and accompanied by hydride transfer was discovered and systematically investigated. A scheme providing for the formation of zirconacyclopentane complexes was proposed for the mechanism of the reaction.Institute of Organic Chemistry, Ural Branch, Russian Academy of Sciences, 450054 Ufa. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1187–1196, May, 1992.