Conduction mechanism in amorphous Si films

dc conductivity as a function of temperature has been measured for as-evaporated and annealed films of amorphous Si, grown by the vacuum evaporation technique. The experimental data suggest that conduction in the higher temperature range (～175–300 K) is by the thermally activated holes in the localized states near the valence band edge while conduction in the lower temperature range (～77–175 K) is found to be thermally assisted tunnelling in the localized states near the Fermi level. The activation energy for both the processes is found to increase with an increase in the annealing temperature. The average hopping distance, calculated for conduction near the Fermi level, is also found to increase with an increase in the annealing temperature.     

Synthesis and molecular structure of tricarbonyl(diphenyl ditelluride)diiodoiron (CO)3FeI2(Te2Ph2) and tricarbonyldiiodo[iodo(phenyl)tellurido]iron (CO)3FeI2(PhTeI): First example of the coordination of unstable PhTeI to the transition metal atom

A reaction of the tetramer [PhTeI]₄ with Fe(CO)₅ gave the monomeric complex (CO)₃FeI₂(Ph₂Te₂) (I) containing a diphenyl ditelluride molecule linked with cis-tricarbonyldiiodoiron. According to X-ray diffraction data, the Fe-Te distance in complex I (2.5724(6) ?) is appreciably shorter than the sum of the covalent Fe and Te radii and the Te-Te bond (2.7705(5) ?) is only slightly longer than that in free Ph₂Te₂ (2.705(1) ?). In the reaction of Fe(CO)₅ with PhTeI₃, a complex with PhTeI as a ligand to the transition metal atom was obtained for the first time. Unlike free PhTeI, the resulting complex (CO)₃FeI₂(PhTeI) (II) is stable in air at room temperature for several days. According to X-ray diffraction data, the ligand PhTeI (Te-C 2.126(4) ?, Te-I(3) 2.7548(5) ?) is stabilized by the coordination of tellurium to both the iron (Te-Fe 2.5451(6) ?) and iodine atoms (Te(1)-I(1) 3.1634(5) ?). The latter coordination probably involves the vacant d orbital of tellurium and the lone electron pair on the iodide ligand. Original Russian Text ? Yu.V. Torubaev, A.A. Pasynskii, P. Mathur, 2008, published in Koordinatsionnaya Khimiya, 2008, Vol. 34, No. 11, pp. 807–811.     

Synthesis, spectral and oxidase studies of a new diamide copper(II) complex with pendant benzimidazolyl groups

A new benzimidazole-based diamide ligand-N,N'-bis(alanine-2-benzimidazolyl) hexanediamide (ABHA) has been synthesized and utilized to prepare Cu(II) complexes of general composition [Cu(ABHA)X2].nH2O,where X is an exogenous anionic ligand (X=Cl-,NO3-). Low temperature EPR spectra has been obtained that shows gparallel>gperpendicular>2.0024, indicating a tetragonal geometry in the solution state. The complexes display a quasi-reversible redox wave due to the Cu(II)/Cu(I) reduction process. E1/2 values shift anodically as NO3-相似文献   

White-light-induced fragmentation of methane

We experimentally probe molecular ionization and dissociation of methane molecules in the gas phase upon their irradiation by intense pulses of white light that spans the wavelength range 500-850 nm. White light pulses are generated upon irradiation of BK7 glass by 36-fs-long pulses of intense 820 nm laser light. Comparison is made of the molecular fragmentation patterns obtained using white light that is depolarized with those obtained using single-color (820 nm) light that is highly chirped. On the basis of such comparison, we make hitherto-unavailable estimates of the in situ intensity of white light pulses. Results obtained using white light also indicate that resonances apparently do not play any role in the ionization dynamics that ensue upon irradiation by intense, broadband light; neither are the dynamics affected by the polarization properties of the 820 nm light that is used to generate the white light.     

Determination of palladium in deoxo catalysts by differential pulse voltammetry

A differential pulse voltammetric (DPV) method is proposed for the determination of palladium in deoxo catalysts, which are used in recombination units of the cover gas system of nuclear reactors. The electrode system consists of hanging mercury drop electrode (HMDE)/ platinum auxillary/ Ag-AgCl reference electrode. The supporting electrolyte consists of 0.02 M diammonium tartrate + 0.08 M ammonia-ammonium chloride buffer at pH 9.0. Fe, Cu, Pb, Ni, Co and Zn did not interfere. The interference by Cd could be eliminated using 0.005 M EDTA. The relative standard deviation of the proposed method was about 4.0% at ∼ 0.5% palladium content in the catalyst. The method is simple, rapid and free from any possible interferences. Received: 8 December 1998 / Revised: 11 January 1999 / Accepted: 18 January 1999     

Scale invariant amplitude modulated phase-only filtering

A new synthetic discriminant-function-based amplitude modulated phase-only filtering technique is proposed for scale invariant pattern recognition. This technique has been found to yield improved correlation output when compared with the alternate techniques. The proposed technique is inherently suitable for optical implementation using the currently available spatial light modulators. Simulation results confirm the effectiveness of the proposed technique.     

Strong optical fields induce ultrafast rearrangement of H-atoms in ethanol molecules

H-atoms in C₂H₅OH are rearranged by strong optical fields generated by intense, 100 fs long infrared laser pulses to form new bonds that lead to the H ₃ ⁺ molecular ion. This observation appears to be against the expectation that exposure of molecules to intensities of the order of 10¹⁵ W cm^?2 inevitably lead to multiple ionization of molecules followed by instantaneous Coulomb explosion into fragments. The polarization dependence of the H ₃ ⁺ signal and of the energy content of H ₃ ⁺ ions lead to believe that H-atom rear-rangement in ethanol occurs within a single 100 fs pulse.     

Limited volume thin film deposition on geometrically complicated substrates

In this paper we report a study on the elastic scattering of electrons by lithium and sodium atoms in the presence of circularly polarized resonant laser field within the framework of the two-state rotating wave approximation. The effect of laser on projectile electrons is described by Volkov states. The frequency of the laser field is chosen to match with the 2s–3p (3s–3p) transition frequency in lithium (sodium) atoms. The total and differential elastic cross sections with single photon exchange are calculated for intermediate energies (50–150 eV) and laser intensity (10⁷–10¹¹ W cm^-2). An erratum to this article can be found online at http://dx.doi.org/. An erratum to this article can be found at     

Working group report: Quantum chromodynamics sub-group

This is the report of the QCD working sub-group at the Tenth Workshop on High Energy Physics Phenomenology (WHEPP-X).      

Electrochemical behavior of different structural states of the alloy Ti60Ni40

Potentiodynamic polarization studies were carried out on nanocrystalline I, nanocrystalline II and nanocrystalline III states having crystallite size 35 ± 5 nm, 18 ± 2 nm and 10 ± 2 nm of the alloy Ti₆₀Ni₄₀ in 1 M H₂SO₄ aqueous medium. It was observed that the nanocrystalline III state exhibits superior corrosion resistance as compared to the nanocrystalline II and nanocrystalline I states of the alloy Ti₆₀Ni₄₀. XPS studies were also performed after corrosion test and it was observed that nanocrystalline III state contains only Ti²⁺ and Ti⁴⁺ species whereas nanocrystalline I and nanocrystalline II state contains Ti²⁺, Ti³⁺and Ti⁴⁺ along with some unoxidized metallic Ti⁰ in the case of nanocrystalline I state. Thus the small crystallite size and the presence of only Ti²⁺ and Ti⁴⁺ species in the form of TiO and TiO₂ leads to the formation of a protective oxide film which is adherent, stable and improves the corrosion resistance of the nanocrystalline III state of the alloy Ti₆₀Ni₄₀.