A combined experimental and theoretical approach for structural study on a new cinnamoyl derivative of 2-acetyl-1,3-indandione and its metal(II) complexes

The synthesis, structure and spectral properties of a new cinnamoyl derivative of 2-acetyl-1,3-indandione (2AID), p-fluoro-cinnamoyl-1,3-indandione, LH and its metal(II) complexes with Cu(II), Zn(II) and Cd(II), are described. In order to verify the molecular structure of the free ligand and its metal complexes, model geometries based on the spectroscopic data were optimized using quantum chemical methods. The experimental spectroscopic data (IR and NMR) of the ligand, LH, complemented by the calculated ones, show that it exists in the exocyclic enolic form in the gas phase, solution and solid state. Good quality single crystals of Cd(II) complex were obtained from a DMSO solution and were studied by means of single-crystal X-ray diffraction. The data show bidentate coordination of the ligand and two DMSO molecules coordinated to the metal centre, thus forming a complex with octahedral geometry. On the contrary, the spectroscopic data on the amorphous samples indicate a square planar geometry of the Cu(II) complex and distorted octahedral geometry for Zn(II) and Cd(II) complexes with two water molecules coordinated to the metal centre. The used quantum chemical method for structure optimization of the transition metal complexes, B3LYP/LANL2DZ, shows very good agreement with the crystallographic data and, therefore, was also employed for structural determination for the non-crystalline complexes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Incorporation of group III,IV and V elements in 3C–SiC(1 1 1) layers grown by the vapour–liquid–solid mechanism

We report on a comparative investigation of the incorporation of group III, IV and V impurities in 3C–SiC heteroepitaxial layers grown by the vapour–liquid–solid (VLS) mechanism on on-axis α-SiC substrates. To this end, various Si-based melts have been used with addition of Al, Ga, Ge and Sn species. Homoepitaxial α-SiC layers grown using Al-based melts were used for comparison purposed for Al incorporation. Nitrogen incorporation depth profile systematically displays an overshoot at the substrate/epilayer interface for all the layers. Ga and Al incorporations follow the same distribution shape as N whereas this is not the case for the isoelectronic impurities Ge and Sn. This suggests some interaction between Ga/Al and N coming from the high bonding energy between the group III and V elements, which does not exist with Ge and Sn. This is why both incorporate as a cluster. A model of incorporation is proposed taking into account metal-N and metal-C bonding energies together with the solid solubility of the corresponding nitrides.     

Structure and properties of a series of 2-cinnamoyl-1,3-indandiones and their metal complexes

A series of seven 2-cinnamoyl-1,3-indandiones and their metal(II) complexes were synthesized and characterized by means of spectroscopic (IR, NMR, electron absorption and emission spectroscopy) and/or single-crystal X-ray diffraction methods. The optical spectra of the organic compounds show very strong absorption in the visible region and weak fluorescence with moderate to strong Stokes shift. The effect of concentration, water addition and metal ion complexation on the optical properties was also studied. In search of potential practical application, the complexation of 2-cinnamoyl-1,3-indandiones with metal(II) ions was investigated. A series of non-charged complexes with Cu(II), Cd(II), Zn(II), Co(II) and Ni(II) was isolated and analyzed by elemental analyses and IR. Most of the complexes show presence of water molecules, most probably coordinated to the metal ion, thus forming octahedral geometry. For the paramagnetic Cu(II) complexes a distorted, flattened tetrahedral structure is proposed, basing on the EPR data. The optical properties of the metal complexes, however, do not differ appreciably from those of the free ligands.     

XPS studies of short pulse laser interaction with copper

The effect of laser ablation on copper foil irradiated by a short 30 ns laser pulse was investigated by X-ray photoelectron spectroscopy. The laser fluence was varied from 8 to 16.5 J/cm² and the velocity of the laser beam from 10 to 100 mm/s. This range of laser fluence is characterized by a different intensity of laser ablation. The experiments were done in two kinds of ambient atmosphere: air and argon jet gas.The chemical state and composition of the irradiated copper surface were determined using the modified Auger parameter (α′) and O/Cu intensity ratio. The ablation atmosphere was found to influence the size and chemical state of the copper particles deposited from the vapor plume. During irradiation in air atmosphere the copper nanoparticles react with oxygen and water vapor from the air and are deposited in the form of a CuO and Cu(OH)₂ thin film. In argon atmosphere the processed copper surface is oxidized after exposure to air.     

Time stepping for vectorial operator splitting

We present a fully implicit finite difference method for the unsteady incompressible Navier-Stokes equations. It is based on the one-step θ-method for discretization in time and a special coordinate splitting (called vectorial operator splitting) for efficiently solving the nonlinear stationary problems for the solution at each new time level. The resulting system is solved in a fully coupled approach that does not require a boundary condition for the pressure. A staggered arrangement of velocity and pressure on a structured Cartesian grid combined with the fully implicit treatment of the boundary conditions helps us to preserve the properties of the differential operators and thus leads to excellent stability of the overall algorithm. The convergence properties of the method are confirmed via numerical experiments.     

Interaction of oxygen with a Mo(111) surface

Oxygen adsorption on a Mo(111) surface is investigated at low pressures (10^?7 to 10^?5 Pa) and room temperature by Auger electron spectroscopy (AES), low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS) and ultra-violet photoelectron spectroscopy (UPS). In agreement with previous studies it is established that the surface is not reconstructed during adsorption and the oxygen forms no ordered structures. On the basis of kinetic and spectroscopy data, the formation of two adsorption states on the surface within 1 monolayer is established. The valence band of a clean surface is studied in detail. An attempt is made to ascribe the peaks obtained to definite d states. The interaction between O₂ and Mo(111) is discussed in terms of the results obtained and a comparison with the O₂/W(111) system is made.     

Hyperfine splitting and isotope shift in the optical transition of Eu isotopes and electromagnetic moments of Eu

The laser-induced resonance fluorescence in an atomic beam was used in order to measure the hyperfine splitting of the 4f ⁷ 6s ² and 4f^{7 6s6p} levels in ^151,153,155Eu isotopes. The hfs constants A and B of the unstable ¹⁵⁵Eu were determined for the first time: MHz, MHz and MHz. With these data and after corrections for second-order hyperfine structure perturbations the nuclear moments of ¹⁵⁵Eu were deduced: n.m. and b. In addition new and more precise values of the hfs constants of the excited state for the stable ^151,153Eu were obtained. They are as follows: MHz, MHz and MHz, MHz. The hyperfine anomalies % and % were extracted from the corrected hfs constants. Received 28 July 1999 and Received in final form 14 January 2000     

Vibrational behavior of matrix‐isolated ions in Tutton compounds IV. Infrared spectroscopic study of NH4+ and SO42‐ ions included in nickel sulfates and selenates

Infrared spectra of K₂Ni(SeO₄)₂·6H₂O and (NH₄)₂Ni(SeO₄)₂·6H₂O containing SO₄^2‐ ions and those of K₂Ni(SO₄)₂·6H₂O and K₂Ni(SeO₄)₂·6H₂O containing NH₄⁺ ions are presented and discussed in the region of ν₃ and ν₁ of the sulfate ions and in the region of ν₄ of the NH₄⁺ ions, respectively. The SO₄^2‐ ions matrix‐isolated in the selenate matrices (approximately 1 mol%) exhibit three bands for ν₃ and one band for ν₁ in agreement with the low site symmetry C₁ of the host selenate ions. The NH₄⁺ guest ions included in the potassium sulfate matrix are characterized also with three bands for ν₄. However, the ammonium ions in (NH₄)₂Ni(SeO₄)₂·6H₂O as well as those included in K₂Ni(SeO₄)₂·6H₂O display four infrared bands corresponding to ν₄ due probably to some kind of disorder of the ammonium ions. The extent of energetic distortion of the isomorphously included sulfate ions as deduced from the values of Δν₃ and Δν_max is commented. The spectroscopic experiments reveal that the SO₄^2‐ guest ions are weaker distorted in the selenate matrices as compared to the same ions in the neat sulfates due to the larger unit‐cell volumes of the selenate compounds. The band positions of the water librations in the host potassium compounds are affected by the included ammonium cations. The formation of hydrogen bonds between the NH₄⁺ guest ions and the XO₄^2‐ host ions leads to a decrease in the proton acceptor capabilities of the anions and as a result the hydrogen bonds weaken on going from the neat potassium compounds to the mixed crystals. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

XPS investigation of a-Si : H thin films after light soaking

Amorphous hydrogenated silicon thin films prepared by homogeneous chemical vapour deposition have been studied. The Si2p, O1s and C1s electron spectra have been recorded after different light soaking times using repeated 100 mW/cm² white light illumination and X-ray photoelectron spectroscopy (XPS) measurements. The change of the position and intensity of the Si2p peak has been observed after light soaking and is explained by the transformation of the Si–H bonds. The correlation between the micropore density in a-Si : H film and the binding energy of Si2p electrons is demonstrated.