bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Analysis and Structures Spherical Crystals of Very Clean Au, Cu and Au-Cu Alloys Grown from a Drop of Melt
Authors: Grosser B. , Menzel E. 
Published: February 2015

Surface impurities on spherical Au and Cu crystals grown from a drop of melt on graphite in UHV were analyzed by Auger electron spectroscopy after the metals had been cleaned by melting resp. roasting in air. Crystals of Au-Cu alloys grown by the same technique show enrichment of the less abundant component.
The well known reconstructions Au(001)(5×20) and Au(111)(23×1) could not be detected by RHEED and LEED on cleaned Au crystals. But both structures were confirmed on crystals of Au + 45 at ppm Cu. Au(110)(1×2) was present on cleaned and weakly Cu alloyed Au crystals.
Coordination of Rhodium(III) in Dilute Aqueous Solutions in Presence of Chloride Anion
Authors: Caminiti R. , Atzei D. , Cucca P. , Squintu F. 
Published: February 2015

Dilute aqueous solutions of Rhodium (III) at the Cl1/Rh(III) ratios 4.86 and 10.7 have been X-ray examined. Octahedral Rh(H2O)6
3+ and Rh(H2O)3Cl3 complexes are the species which are consistent with the correlation functions and the structure functions. The average number of bonded chloride ions per Rhodium atom has been determined and the reliability of the structural information is critically examined.
The influence of the temperature on the substitution of water molecules by chloride ions is confirmed by using Raman spectroscopy.
207Pb and 205Tl NMR on Perovskite Type Crystals APbX3 (A = Cs, Tl, X = Br, I)
Authors: Sharma Surendra , Weiden Norbert , Weiss Alarich 
Published: February 2015

By 205Tl and 207Pb NM R the chemical shift in polycrystalline samples of binary halides AX, BX2 and ternary halides ABX3 (A = Cs, Tl; B = Pb; X = Br, I) was studied at room temperature. The chemical shift tensors δ ( 205Tl) and δ (207Pb) were determined in magnitude and orientation on single crystals of the orthorhombic TlPbI3. The components of the δ(205Tl) tensor are δx (205Tl) || a = 611ppm; δy (205Tl) || b = 680 ppm; δZ(205Tl) || c = 1329 ppm; δiso(205Tl) = 873.3 ppm (with respect to 3.4 molar aqueous solution of TlOOCCH3). The chemical shift tensor of 207Pb in TlPbI3 shows two orientations. One of them is: δx (207Pb) = 3760 ppm, inclined 30° from b towards c, δy(207Pb) || a = 3485 ppm, δz(207Pb) = 2639 ppm inclined 120° from b towards c. δiso(207Pb) = 3295 ppm (with respect to saturated aqueous solution of Pb(NO3)2). The results are discussed with respect to the crystal structure and a model to explain orientation and anisotropy of the tensors δ(205Tl) and δ(207Pb) in TlPbI3 is proposed.
In the system CsPbBr3-x Ix δ(207Pb) was studied on polycrystalline samples. The chemical shift increases with increasing x and negative excess shift is observed.
High-Resolution Infrared Spectrum of Diazirine, H2CN2. Rovibrational Analysis of the Methylene Deformation Band
Authors: Gambi A. , Baldacci A. , Giorgianni S. 
Published: February 2015

Abstract
The infrared spectrum of diazirine has been recorded at Doppler resolution with a high informa­tion Fourier transform spectrometer. The ν3 fundamental has been reinvestigated and the overall assignment of the rovibrational transitions has been carried out. From the least-squares analysis a more accurate set of molecular constants including the sextic centrifugal distortion constants has been determined for the level υ3 = 1 and will be reported here. The higher resolution achieved here allowed the assignment of weaker lines and many Q branch transitions. Moreover many blended lines have now been resolved and could be properly assigned.
Gravitation as a Composite Particle Effect in a Unified Spinor-Isospinor Preon Field Model I
Authors: Stumpf H. 
Published: February 2015

Abstract
The model is defined by a selfregularizing nonlinear preon field equation, and all observable (elementary and non-elementary) particles are assumed to be bound (quantum) states of fermionic preon fields. Electroweak gauge bosons, leptons, quarks, gluons as preon composites and their effective dynamics etc. were studied in preceding papers. In this paper gravitons are introduced as four-preon composites and their effective interactions are discussed. This discussion is performed by the application of functional quantum theory to the model under consideration and subsequent evaluation of a weak mapping procedure, both introduced in preceding papers. In the low energy limit it is demonstrated that the effective graviton dynamics lead to the complete homogeneous Einstein equations in tetrad formulation.
Exact Analytical Solutions of the Non Polynomial Oscilator
Authors: Roy Pinaki , Roychoudhury Rajkumar 
Published: February 2015

Abstract
We derive new exact (analytical) solutions of the non polynomial oscillator V(x) = x2 + λx2 / (1 + g x2) in one as well in three dimensions. The solutions are derived within the framework of supersymmetric quantum mechanics, and it is shown that exact solutions exist when the coupling constants satisfy a supersymmetric constraint.
Vector Theory of Gravity with Substratum
Authors: Winterberg F. 
Published: February 2015

Abstract
A vector theory of gravity with substratum is proposed, which reproduces all the empirically verified linear and nonlinear predictions of Einstein's gravitational field equations, but unlike Einstein's theory, it does not lead to the unphysical singularities and causality-violating solutions permitting travel back in time. In the proposed alternative theory, a substratum or ether is the cause of all relativistic effects, and for this reason is assumed to obey a nonrelativistic equation of motion, an assumption which allows the substratum to consist of densely packed positive and negative Planck mass particles. A substratum of this kind can produce the vacuum fluctuations, needed to be in agreement with the empirical evidence, but avoids the paradox of infinite gravitationl forces, predicted by a divergent zero point energy, the only one possible under the strict adherence to the kinematic interpretation of special relativity.
Tensorial Representation of ƒ′ for Nb in Lithium-niobate, LiNbO3
Authors: Petcov A. , Kirfel A. , Fischer K. 
Published: February 2015

Abstract
Using Synchrotron radiation, the dependence of resonant phenomena (absorption, fluorescence and Raman scattering) on the angle between the polarisation plane of the incident radiation and the polar c-axis in ferroelectric Lithium-niobate, LiNbO3, was studied in the vicinity of the Nb K-absorption edge. Applying the "optical theorem", the observed dipolar anisotropics can be explained in terms of the projection of the dipole momentum operator on the polarisation vector of the X-ray photons.
Nonlinear Thermodynamics of Moving Material Surfaces in Electric Fields
Authors: Wallschlager H. 
Published: February 2015

Abstract
A continuum-mechanical formalism is presented for the phenomenological description of moving, curvilinear, material surfaces in electric fields in interaction with volume-phases. In addition to conventional equations (balance and constitutive laws) the explicit use of relations for the surface geometry is introduced. A method to establish nonlinear constitutive equations by tensorial and thermodynamical considerations is proved to be applicable to two-dimensional continua. The resulting equations for boundaries interacting with adjacent volumes are of practical importance for the selfconsistent calculation of boundary values. The physical meaning of the different relations is discussed.
Calculation of the Excitation Energies of a Hydrogen Impurity in Niobium
Authors: Sommer F. T. , Hau K. , Frodl P. , Wahl F. 
Published: February 2015

Abstract
Recent calculations of the electronic structure of a hydrogen atom in niobium using microscopic first principles are extended in that the dynamical behaviour of a hydrogen impurity centre in Nb is considered quantummechanically. The calculated excitation energies are in good agreement with experimental values of time of flight-spectra taken from NbH0.05.
Reaction of Bromous Acid with Bromide in the Presence of Silver Ions
Authors: Försterling H. D. , Schreiber H. 
Published: February 2015

Abstract
The reaction HBrO2 + Br- + H + →2 HOBr, which is the most important control reaction in the Belousov-Zhabotinsky (BZ) system, is investigated in competition to the AgBr precipitation reaction Ag+ + Br- →AgBr. It turns out that the bromite-bromide reaction starts even in the presence of Ag+ in high concentration; the rate of consumption of bromite by bromide, however, is slowed down significantly if silver ions are present in the system. The experiments reveal that the AgBr precipita­ tion reaction proceeds in a series of several steps, starting with a fast equilibrium. This way different experimental results on the influence of silver ions on the kinetics of the BZ reaction may now be better understood.
Thermoanalytische Untersuchungen zur Rückoxidation von Ba2YCu3O6+x
Authors: Teske Chr. L. , Müller-Buschbaum Hk. 
Published: February 2015

Abstract
The reoxidation reaction of Ba2YCu3O6+ x forming the superconducting ceramic material Ba2YCu3O6 93 is studied by thermoanalytical methods (DTA and TG). The exothermal oxygen uptake in pure O2-atmosphere is at a maximum rate in the range of 230-330 °C (≈ 150min). The reoxidation temperature can be lowered by treatment of Ba2YCu3O6 0 in Ar : H2 = 1: 1 atmosphere but the uptake of greater amounts of hydrogen prevents the material from becoming super-conducting again at low reoxidation temperatures. The process has an activation energy Ea = 70.9 ± 2kJ Mol and a reaction enthalpy ΔH = - 86.7kJ/Mol Ba2YCu3O6.0 (normalized to a 1/2 O2 basis) which is estimated from DTA-data.
The Iodine Hvperfine Structure in the Microwave Spectrum of Ethyl Iodide: Nuclear Quadrupole and Spin Rotation Coupling
Authors: Gripp Joachim , Dreizler Helmut 
Published: February 2015

Abstract
Some rotational transitions of ethyl iodide, CH3CH2I, have been reinvestigated by microwave Fourier transform (MWFT) spectroscopy. The iodine hyperfine structure splittings were first ana lyzed using a direct diagonalization procedure of the complete quadrupole Hamiltonian matrix. The results of this analysis showed deviations from our measurements up to 60 kHz. A new analysis using additional spin rotation coupling matrix elements reproduces our measurements within the experi­mental error limit and decreases the standard deviation of the least squares fit from 28 kHz to only 4 kHz.
35Cl Nuclear Quadrupole Relaxation in Pyridinium Hexachlorostannate (IV)
Authors: Tai Yutaka , Ishikawa Atsushi , Horiuchi Keizo , Asaji Tetsuo , Ikeda Ryuichi 
Published: February 2015

Abstract
The temperature dependence of the 35Cl quadrupole spin-lattice relaxation time T1Q is reported for the three known resonance lines of pyridinium hexachlorostannate (IV). With increasing temper­ature, a sharp decrease of T1Q is observed below the phase transition temperature of 331 K. This decrease can be explained by reorientational motions of the complex anions. The activation energy for the motions is determined as 97 and 63 kJmol-1 from the T1Q data obtained from the highest-frequency resonance line and the remaining two lines, respectively. The two different barriers observed for the reorientation of a single anion suggest the existence of anisotropy of the anionic motion. An anomalous T1Q vs. T-1 relation observed in an intermediate-temperature region is discussed by referring to the cationic motion.
Interionic Potentials and MC Simulations of Molten AgCl
Authors: Margheritis C. , Sinistri C. 
Published: February 2015

Abstract
Monte Carlo simulations on molten AgCl were carried out in order to test the applicability of the interionic potentials recently proposed for this salt in the solid phase. None of the literature potentials can be used as such: in all cases pairs of like ions reach too short distances of approach causing the collapse of the system. It was proved that, in order to obtain equilibration of the system, the pair potentials of like ions must be recalculated.
On the basis of these modified potentials, MC simulations of molten AgCl were carried out at 728 (m.p.), 1000 and 1500 K. The polarization energy effect was also analyzed with the use of a soft ion model.
Acetonitrile-Water Solutions of Sodium Halides: Viscosity and Self-Diffusion of CH3CN and H2O
Authors: Hawlicka Ewa 
Published: February 2015

Abstract
Measurements of the viscosity of solutions of NaCl and Nal in acetonitrile-water mixtures at 25 °C, and of the self-diffusion coefficients of CH3CN and H2O in these liquids, using 14C and 3H as tracers, are reported. The results confirm the previously postulated preferential solvation of the ions by acetonitrile.
Synthesis, Structure, and Spectral Properties of Pvrylium Salts and Their Derivatives. II.5-(Benzyliden)- and 5-(Cinnamvliden)-5,6,7,8-Tetrahydro-1,3-Diphenyl-2-Benzopyrylium Salts
Authors: Nikolov P. , Deligeorgiev T. , Tyutyulkov N. , Kanev I. 
Published: February 2015

Abstract
The synthesis, structure and spectral properties of a group of dyes with a pyrylium ring are described. Quantumchemical calculations indicate that the chromophore system has a structure corresponding to that of the polymethine dyes.
A Monte Carlo Study on a Magnesium Cyclen Complex
Authors: Ruangpornvisuti Vithaya W. , Rode Bernd M. 
Published: February 2015

Abstract
A Monte Carlo simulation has been performed to study the hydration of the magnesium complex of 1,4,7,10-tetraazacyclododecane (cyclen). An intermolecular potential function for magnesium cyclen complex and water, derived from ab initio calculations was used. The first hydration shell results to consist of 18 water molecules.
Dielectric Relaxation Study of ZnCl2 and ZnBr2 Solutions in Water/DMSO Mixtures
Authors: Galstian A. , Stockhausen M. 
Published: February 2015

Abstract
Dielectric spectra have been measured for the title systems up to 72 GHz at 20 °C with salt concentrations ≤ 1 mol/l. The results are described by a superposition of Debye terms. Two terms are sufficient for binary water/DMSO mixtures, while two additional lower frequency ones are required when salt is added. The results for both halides differ only little. The relaxation strengths of a term ascribable to ionic complexes and a term ascribable to water/DMSO (2:1) complexes vary in opposing sense, demonstrating the competition between those complexes.
PVT Measurements on 4′-n-Octyl-Biphenyl-4-Carbonitrile (8CB) up to 300 MPa
Authors: Sandmann M. , Würflinger A. 
Published: February 2015

Abstract
P, Vm , Tdata have been measured for the smectic, nematic and isotropic phases of 4'-n-octyl-biphen-yl-4-carbonitrile (8CB) in the temperature range 300-370 K and pressures up to 300 MPa. At atmospheric pressure all phase transitions appear to be of first order due to a discontinuity in the density. The volume change at the smectic A -nematic transition is only a tenth of the volume change at the clearing temperature. At moderate pressures below 80 MPa the SA -N transition could be detected as a discontinuity in the period of oscillation in measurements with a high-pressure vibrating tube densimeter. At higher pressures the discontinuity seems to die away, possibly indicating a change from first order to second order transition. From the volume changes and the slopes of the transition lines we calculate the enthalpy changes at the phase transition. The p, Vm , T data enable us to calculate the volume part of the entropy and the molecular field parameter γ=δln TNI/δln VNI .
New Exact Solutions for a Generalized Breaking Soliton Equation
Authors: Gao Yi-Tian , Hong Woopyo , Tian Bo 
Published: February 2015

Abstract
The breaking soliton equations are a class of nonlinear evolution equations of broad interest in physical and mathematical sciences. In this paper, the application of the generalized tanh method with symbolic computation leads to new exact solutions for a generalized breaking soliton equation, of which the previously-obtained solutions are the special cases.
Synthesis and Crystal Structures of ATi[Nb6Cl18] Compounds (A = K, Rb, Cs, In, Tl)
Authors: Nägele A. , Anokhina E. , Sitar J. , Meyer H.-J. , Lachgar A. 
Published: February 2015

Abstract
New quaternary niobium cluster chlorides corresponding to the general formula ATi[Nb6Cl18] (A = K, Rb, Cs, In, Tl) have been synthesized in sealed quartz tubes at 720 °C, starting from stoichiometric amounts of NbCl5, niobium metal, TiCl3, and ACl (A = K, Rb, Cs), or In or Tl metals. The structures of RbTi[Nb6Cl18] and CsTi[Nb6Cl18] were determined using single­ crystal X-ray diffraction. RbTi[Nb6Cl18] crystallizes in the rhombohedral crystal system, space group R3̄ (no. 148), Z = 3, with lattice parameters: a = 9.163(4), c = 25.014(14) Å (hexagonal setting). The structure refinement converged to R1 = 0.044 and wR2 = 0.058 for all data. In this structure, discrete [Nb6Cl18]4-cluster units are linked by Rb+ and Ti3+ cations, located in a 12-coordinated anticubeoctahedral and octahedral chloride coordination environment, respectively. In contrast, CsTi[Nb6Cl18] crystallizes in the trigonal crystal system, space group P3̄1c (no. 163), Z = 2. The lattice parameters were determined to be a = 9.1075(6), c = 17.0017(8) Å. The structure refinement gives the reliability factors R1 = 0.029 and wR2 = 0.063 for all data. The structure is built up of discrete octahedral [Nb6Cl18]4- cluster units, linked by Cs+ and Ti3+ cations which are located in a distorted hexagonal antiprismatic and octahedral chloride coordination environment, respectively. The structures of the compounds ATi[Nb6Cl18] (A = K, In, Tl) were found to be isotypic with RbTi[Nb6Cl18], and their unit cell parameters were refined using X-ray powder diffraction analysis.
Zur Koordinationschemie des 2,2′-Dipyridyldiselenids (PySeSePy), Teil 2 [1] Komplexe mit Mangan, Kupfer und Zink/ The Coordination Chemistry of 2,2′-Dipyridyldiselenide (PySeSePy), Part 2. Complexes with Manganese, Copper and Zinc
Authors: Kienitz Carsten O. , Thöne Carsten , Jones Peter G. 
Published: February 2015

Abstract
The coordination chemistry of 2,2′-dipyridyldiselenide (PySeSePy) towards mangane­se, copper and zinc centres has been studied. The complexes [MnBr2-N,N′-(PySeSePy)] (1), [CuBr2-N,N′-(PySeSePy)] (2), [Cu-(μ-Br)-N,N′-(PySeSePy)]2 (3), [Cu-(μ-Br)-{μ-N,N′-(PySeSePy)}]n (4), [Cu-(μ-Cl)-N,N′-(PySeSePy)]2 (5), [Zn(OOCC6F5)2-N,N′-(PySeSePy)] (6) and [Zn (OSO2CF3)2-N,N′-(PySeSePy)] (7) have been synthesised and the crystal structures of 1, 3, 4 and 6 determined. 1, 3 and 6 display seven-membered metallacycles with tetrahedral coordination of the metal centres. In these cases 2,2′-dipyridyldiselenide acts as a chelating ligand. In the polymeric complex 4, 2,2′-dipyridyldiselenide acts as a bridging ligand. All com­ plexes display selenium-selenium single bonds with an average length of 232 pm. In contrast to the analogous chloro and nitrato complexes, the zinc complexes 6 and 7 are not dissociated in solution, as evidenced by 77Se NMR experiments. The corresponding resonances are shifted downfield in comparison with the ligand.
Zur Chemie von Mischphasen in komplexen Zustandsdiagrammen Das System Bi2O3/Bi2Se3/Bi2Te3/Chemistry of Mixed Crystals in Complex Phase Diagrams The System Bi2O3/Bi2Se3/Bi2Te3
Authors: Schmidt P. , Oppermann H. 
Published: February 2015

Abstract
Pseudoternary System Bi2O3/Bi2Se3/Bi2Te3, Phase Diagram, Thermodynamic Data The phase diagram of the pseudoternary system Bi2O3/Bi2Se3/Bi2Te3 is found to include a quaternary solid solution Bi2O2 (TexSe1-x) and ternary, intermetallic mixed crystals Bi2(TexSe1-x)3. Using thermodynamic modeling of the solid solutions it is possible to calcu­ late complex heterogeneous equilibria between all phases of this phase diagram. As a result we can thermodynamically describe the observed phase relations:
Bi2(TexSe1-x)3 ⊿H°m(298) = 0; ⊿S°m(298) = R[xlnx + (1-x)ln(1-x)]
Bi2O2(TexSe1-x) ⊿H°m(298) = Ω · x(1-x); O⊿S°m(298) = R/4 [xlnx + (1-x)ln(1-x)]
Ω = 0,6 kcal/mol
Kristallstruktur und spektroskopische Charakterisierung von Hexamethyl- disilazan-Aluminiumtrichlorid [(H3C)3Si]2NH ∙ AlCl3 / Crystal Structure and Spectroscopic Characterisation of Hexamethyl- disilazane-trichloroalum inum [(H3C)3Si]2NH ∙ AlCl3
Authors: Jansen Martin , Jäschke Thomas 
Published: February 2015

Abstract
By reaction of hexamethyldisilazane with aluminium trichloride in hexane hexamethyldisilazane-trichloroaluminum [(H3C)3Si]2NH • AlCl3 is formed. The adduct has been characterized by MS, IR, Raman, 1H, 13C, 27Al, 29Si NMR spectroscopy, and by a crystal structure determination (1425 independent reflections, R = 0.035). The space group is Pbca with a = 1312,6(5), b = 1182,9(5), c = 1964,7(5) pm; Z = 8. [(H3C)3Si]2NH • AlCl3 forms monomeric units which have point symme­try C1 and exhibit an Al − N bond length of 193,9(3) pm.
19β → 28-Lactonization of Pomonic Acid from Lantana camara roots
Authors: Misra Laxminarain , Laatsch Hartmut 
Published: February 2015

Abstract
Lantana camara L. var. aculeata yielded a triterpenoid, pomonic acid (1). The acid-catalyzed lactonization of this γ-hydroxy acid afforded a rearranged lactone 3, the structure of which was as­ signed by detailed 2D-NMR studies. A reaction mechanism involving a 1,3-butadiene intermediate is proposed.
Polylithiation of Small Molecules. Synthesis and Structure of the Functional Lithium Phosphide [Li(TMEDA)]2[PhPCMe2 C5H4]
Authors: Bildmann Ulrich Jürgen , Müller Gerhard 
Published: February 2015

Abstract
Lithium Phosphides, Cyclopentadienides Treatment of 6,6-dimethylfulvene with LiPHPh in hexane/TMEDA (TMEDA = N,N,N′,N′- tetramethylethylenediamine) affords the monolithiated phosphinomethyl cyclopentadienide [Li(TMEDA)][PhHPCMe2C5H4] (1). Further reaction with LinBu in diethylether/TMEDA leads to the formation of the doubly lithiated phosphidomethyl cyclopentadienide [Li(TMEDA)]2[PhPCMe2C5H4] (2) whose crystal and molecular structure was determined (orthorhombic, space group P212121, a = 9.579(4), b = 12.788(2), c = 24.108(6) Å, Z = 4)
Synthese und Kristallstruktur von (Ph3PAu)4[AuMn(CO)5]2 und (Ph3PAu)3Re(CO)4/ Synthesis and Crystal Structure of (Ph3PAu)4 [AuMn(CO)5]2 and (Ph3PAu)3Re(CO)4
Authors: Richter Markus , Fenske Dieter , Strähle Joachim 
Published: February 2015

Abstract
The reaction of [Mn(CO)5]- with the cluster cation [(Ph3PAu)8]2+ in thf yields the heterometallic cluster [(Ph3PAu)4 [AuMn(CO)5]2 (1) as the main product besides small amounts of (Ph3PAu)3Mn(CO)4. The former crystallizes as 1-thf in form of red blocks in the triclinic space group P1 with a = 1391,0( 1), b = 1426.7( 1), c = 2308.3(2) pm, α = 92.87(1), β = 97.54( 1), γ = 96.43(1)° and Z = 2. The inner Au6 skeleton of the almost centrosymmetrical cluster consists of two Au4 tetrahedra sharing one edge. Two gold atoms bind a Mn(CO)5 fragment, whereas to the other four gold atoms phosphine ligands are coordinated. The Au-Au distances range from 263.2(1) to 281.9(1) pm, and the Au-Mn distances are 256.6(3) and 256.9(2) pm. By the reaction of [(Ph3PAu)8]2+ with [Re2(CO)9]2- the cluster (Ph3PAu)3Re(CO)4 (2) is obtained in low yield besides the homometallic cluster [(AuPPh3)7]+ as the main product. 2 crystallizes from toluene as 2 C7H8 in the form of yellow blocks with the orthorhombic space group Pna21, and a = 1758.7(3), b = 1648.7(5), c = 2049.3(5) pm. The four metal atoms form a planar lozenge with the Re atom in equatorial position. The Re-Au distances range from 271.2(1) to 273.7(1) pm, and the Au-Au distances are 278.2(1) and 278.4(1) pm