bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Formula for the Spectral Line Broadening in Plasmas with Application to the Asymmetry of Ly-α
Authors: Hegerfeldt Gerhard C. , Reibold Reinhard 
Published: February 2015

Abstract
Some time ago, von Waidenfels [4] derived a systematic series expansion of the exact line shape function in case of a single perturber species. In view of the involved mathematics it remained unclear to what physical approximation the first order term of the series corresponds. Here we generalize the approach to two perturber species, one of which is treated quasi-statically (ions), and give a direct physical derivation of the first order term. This term incorporates non-commutativity of ion and electron potentials. In the numerical evaluation for Ly-α it turns out that the noncommutativity effects are washed out to a large extent by the averaging process.
Determination of the Energy Level V0 of Electrons in Liquid Argon over a Range of Densities
Authors: Allen Augustine O. , Schmidt Werner F. 
Published: February 2015

Abstract
The energy level V0 of electrons injected into liquid argon was determined over the range of temperatures and densities in which the electron mobility passes through a maximum. A minimum in V0 was found, not at the density of the mobility maximum as expected, but at a somewhat higher density.
Electrical Conductivity and NMR-Investigations in the A15-and σ-Phase of V-Co Compounds in the High Temperature Range
Authors: Ploumbidis D. , Hüber G. 
Published: February 2015

Abstract
The electrical resistivity of the A15-and σ-phase of V-Co compounds has been measured in the temperature range 300 to 1300 K. Its temperature coefficient is found to be positive for the A15-phase, but negative for the σ-phase. For the same compounds we carried out 55V-and 59Co-Knight shift measurements in the high temperature range (300-1100 K). The 51V-NMR-line corresponding to the central transition (m = +½→m= -½) shows over the entire temperature range the characteristic splitting due to the second-order quadrupole interaction, whereas the 59Co-NMR-line does not show any splitting. Using these NMR measurements we determined for the A15-phase the isotropic and anisotropic parts of the 51V-Knight shift, the quadrupole coupling constant e2qQ/h and the "line width" ⊿B. The experimental results are discussed in the frame of models concerning hyperfine field and electric conductivity of transition metals and their alloys.
Viskositätsabhängigkeit der Fluoreszenzquantenausbeute von Donator-Akzeptor-substituierten trans-Stilbenen in unpolaren wenig viskosen Lösungsmitteln
Authors: Gloyna D. , Kawski A. , Gryczyński I. 
Published: February 2015

Abstract
Fluorescence quantum yields, φf, of donor-acceptor substituted trans-stilbenes, 1, in n-heptane and toluene depend upon the solvent dynamic viscosity η according to the relation ln(φf
-1 - 1) = a ln(η-1)+b. By changing the temperature (278 < T < 343 K) the viscosity was varied. The viscosity dependence of φf can be accounted for by a corresponding viscosity depending radiations less deactivation of the S1 state, which in low solutions is first of all determined by the intramolecular donor-acceptor and universal intermolecular solute-solvent interactions, and then by viscosity.
Kinetics of Acid-Catalysed Hydrolysis of Diethylsuccinate in Dioxane-Water Mixtures
Authors: Khalil Fayez Y . , Abdel-Halim F. M. , Asaad Adel N. 
Published: February 2015

Abstract
The specific rate constants k1 and k2 of the consecutive first-order acid-catalysed hydrolysis steps of diethylsuccinate in dioxane-water mixtures covering the range 0-95% (w/w) of dioxane are determined at 25-55 °C. As the concentration of dioxane increases, the rate of the reaction decreases to a minimum at about 90% (w/w) dioxane, after which it increases again. The ratio k1/k2 was found to be almost constant at the value 2.0. The activation energies of the reaction are independent of solvent composition. Available electrostatic theories regarding the effect of the dielectric constant on the rate are presented, from which the reaction is shown to be an ion-molecular dipole type of interaction. The thermodynamic parameters and the radii of the activated complex at different solvent compositions are calculated and discussed.
Limits of the X-Ray Collimation by One Asymmetrical Bragg Reflection
Authors: Brümmer  , Höche H. R. , Nieber J. 
Published: February 2015

Abstract
In connection with the production of highly collimated X-rays the study of extremely asymmetrical Bragg reflections became of interest. In this paper the so-called extended dynamical theory of X-ray diffraction will be tested experimentally. As a result of this investigations the optimum conditions for X-ray collimation by means of one asymmetrical Bragg reflection are being discussed.
Influence of Rotational Relaxation on Tropospheric OH Laser Induced Fluorescence Measurements
Authors: Gericke K.-H. , Comes F. J. 
Published: February 2015

Abstract
Rotational relaxation of OH molecules in the 2II electronic ground state has been observed to occur in collisions with water molecules with gas kinetic probability. It causes an additional contribution to the already well known sources of interference when LIF is used to monitor tropospheric OH. As the laser generated OH is originally produced mostly in high rotational states, the fast relaxation phenomenon leads to a further population of OH in low rotational states. These states are used to monitor tropospheric OH by spectroscopic methods. The observed effect therefore increases the interference. A mathematical analysis is presented, revealing the effect of all relevant parameters.
Elektrische und optische Eigenschaften von Gd2Cl3 und Tb2Cl3 / Electrical and optical properties of Gd2Cl3 and Tb2Cl3
Authors: Bauhofer Wolfgang , Simon Arndt 
Published: February 2015

Abstract
Electrical and optical properties of Gd2Cl3 and Tb2Cl3 The electrical resistivity of Gd2Cl3 and Tb2Cl3 has been investigated as a function of temperature. Conventional measurements on powder pellets as well as contactless microwave measurements on small single crystals yield a semiconducting behaviour for both componds with energy gaps of about 0.85 eV for Gd2Cl3 and 1.1 eV for Tb2Cl3. The measurements indicate a strong anisotropy of the resistivity. The reflectivity of Tb2Cl3 has been studied in the energy range from 1.1 to 4 eV.
Transition to Semiconducting Characteristics in Liquid Alkalimetal-Antimony-Alloys
Authors: Redslob H. , Steinleitner G. , Freyland W. 
Published: February 2015

Abstract
The paper reports new measurements of the electrical conductivity, thermoelectric power, magnetic susceptibility, and molar volume of liquid Cs-Sb alloys and, partly, Na-Sb and K-Sb alloys. From the temperature and composition dependence of the electronic properties it is concluded that typical semiconducting behavior similar to liquid chalgogen based alloy semiconductors exists over a wide composition range. The change in bonding for 0.25≦XSb≦0.5 is qualitatively discussed and it is found that these liquid alloys are not essentially ionic in character.
Structural Requirements for Intramolecular Charge-Transfer in Excited State of 4-(9-Anthryl)-N,N-dimethylaniline
Authors: Siemiarczuk Aleksander , Koput Jacek , Pohorille Andrzej 
Published: February 2015

Abstract
Excited state kinetics and other photophysical features of 4-(9-anthryl)-N,N-dimethylaniline and two model compounds have been thoroughly examined in order to establish the structural conditions for highly polar excited state formation.
Also quantum chemical calculations by means of INDO/S CI and PCILO methods have been performed to obtain potential energy curves, dipole moments and atomic charge densities for the ground and lowest excited singlet states as a function of the angle of twist between anthryl and dimethylaniline subunits.
Both the experimental and theoretical results confirm the previously proposed TICT (Twisted Intramolecular Charge-Transfer) model predicting the perpendicularity between electron donor and acceptor moieties as a condition for nearly full charge-separation in excited states for some classes of aromatic compounds.
Enskog-Boltzmann-Equation for a Fluid of Nonspherical Particles
Authors: Thurn H. , Hess S. 
Published: February 2015

Abstract
The Enskog-Boltzmann-equation is generalized to fluids of nonsperical particles with fixed orientation, i.e. for overdamped rotational motion. General relations between the interparticle position vector at the instant of contact, the impact parameter and the differential cross section are derived. The dependence of these quantities of the orientations of the colliding particles is studied for the special case of hard ellipsoids.
Thermodynamic Study of Al-Ge-Sn Ternary Alloys by E.M.F. Measurements
Authors: Eslami H. , Gambino M. , Bros J. P. 
Published: February 2015

Abstract
An electrode potential study of liquid Al-Ge-Sn alloys has been conducted with the cell Al | Al3+ in KCl + LiCl | Al in Al-Ge-Sn in the temperature range 683 K ≦ T ≦ 1273 K. Aluminium partial mixing functions were determined for alloys. These measurements allow us to give the surface corresponding to aluminium partial free energy at 1273 K and the liquidus surface of the Al-Ge-Sn phase diagram.
On a Unified Potential Energy Function for Ionic and Non-ionic Bonds and the Question of Chemical Bonding
Authors: Hooydonk G. Van 
Published: February 2015

Abstract
For 39 diatomic ionic and non-ionic molecules, the anomalous behaviour of the spectral para-meters αe and ωχxe with respect to the bond type is reviewed. It is shown that on using a "uni-versal" Sutherland parameter defined as ⊿ = ½kere
2/Dion, the anomalous behaviour disappears. Hard spectroscopic evidence is thus presented, for the first time to the author's knowledge, that just one bond type, in fact an ionic one, can account, in first approximation, for the spectral behaviour of both non-ionic and ionic bonds, H2 included.
On the Existence of Eigenmodes of Linear Quasi-Periodic Differential Equations and their Relation to the MHD Continuum
Authors: Salat A. 
Published: February 2015

The existence of quasi-periodic eigensolutions of a linear second order ordinary differential equation with quasi-periodic coefficient f{ω1t, ω2t) is investigated numerically and graphically. For sufficiently incommensurate frequencies ω1, ω2, a doubly indexed infinite sequence of eigenvalues and eigenmodes is obtained.
The equation considered is a model for the magneto-hydrodynamic “continuum” in general toroidal geometry. The result suggests that continuum modes exist at least on sufficiently ir-rational magnetic surfaces
Singlet-Exciton Energy Transfer in Tetracene-doped Anthracene Crystals as Studied by Time-Resolved Spectroscopy
Authors: Braun A. , Mayer U. , Auweter H. , Wolf H. C. , Schmid D. 
Published: February 2015

Abstract
The time-resolved sensitized fluorescence of tetracene-doped anthracene crystals following a two-photon picosecond-pulse excitation was investigated experimentally as a function of dopant concentration and temperature. Even at the optimum time resolution achieved in these experiments (about 5ps) the time dependence of the host fluorescence was always purely exponential, that of the guest fluorescence a superposition of two exponentials. Thus no time dependence of the energy-transfer rate could be identified. The temperature dependence of the energy-transfer rate is explained tentatively in terms of a "hopping model" (hopping time th ≈ 5.8·10-14s) and thermal reactivation from shallow exciton traps (trap depth 43 cm-1) in the vicinity of the guest molecules.
In pure anthracene crystals the intrinsic exciton lifetime (observed at 20 K) is (5.0 ± 0.5) ns. At higher temperatures it increases to about 15.5 ns at 300 K due to reabsorption processes. Below 20 K it decreases to about 1.5 ns at 1.6 K because of exciton trapping at shallow X-traps (trap depth 23 cm -1). When using conventional one-photon excitation exciton-exciton annihilation was observed with an annihilation constant γss ≈ 1.0 × 10-8 cm3 s-1.
Kinetic and Spectroscopic Behaviour of Proflavin Transients Studied by Pulse Radiolysis
Authors: Solar Sonja , Solar Wolfgang , Getoff Nikola 
Published: February 2015

Abstract
The semireduced transients of proflavin were studied in airfree acid aqueous solutions by a combined pulse radiolysis-computer optimization procedure. The main product, semiquinone (C-radical; 75%), formed with k=6.4 × 109dm3mol-1s-1 , decays by dimerisation (2k=2 × 109dm3mol-1s-1) and dismutation (2k=0.5 x 109dm3mol-1s-1). It possesses several absorption bands (ε270 = 1900, ε360 = 1530, ε460 = 2250 and ε530 = 200 m2mol-1 ). The second transient, R·-species (N-radical; 16.5%), is produced with k=1.4 × 109dm3mol-1s-1 and decays preferentially by transformation into semiquinone with k = 2 × 105s-1; its absorption bands are: ε295 = 2300, ε380 = 1000, ε440 = 5000 and ε680 = 530m2mol-1. Finally H-adducts on various positions of the aromatic ring (8.5%) are arising with k = 0.7 × 109dm3mol-1s-1 , decay according to a pseudo first order reaction, k = 1.1 × 104s-1, and have absorption bands at ε270 = 2100 and ε435 = 1580m2mol-1. The obtained results are of particular interest for the photochemical and photoelectrochemical solar energy utilization.
Limitations of LEED-Structure Determination of Reconstructed Crystal Surfaces
Authors: Jagodzinski H. 
Published: February 2015

Although a strictly ordered reconstructed crystal surface may have the two-dimensional symmetry prescribed by the bulk (two-dimensional subsymmetry of the 3-dimensional space group), it belongs more frequently to a subgroup. In the LEED-pattern a lower symmetry of the translation group can easily be detected on account of the superstructure reflections observed. In this case anti-phase domains can hardly be avoided. An even more difficult situation arises if the symmetry of the point group is violated, although the symmetry of the diffraction pattern is not altered at the end of the reconstruction. Twin domains without changes of lattice constants have to be taken into account.
Dynamical scattering of anti-phase domains is calculated by applying the "Cluster embedded chain"-method for various distributions of domains. It is shown that the incoherent superposition of scattering amplitudes, normally applied in LEED-calculations may lead to serious errors in structure determination. This effect is even more pronounced for twin domains. As an example we discuss the reconstruction of the (001)-surface of Si and Ge, and show that the wellknown (2 X 1)-structure is an averaged structure only, consisting of anti-phase domains with the (4 x 2)-structure. It may be concluded therefrom that none of the present model structures of this reconstruction agrees with this experimental observation.
Ion Formation from Alkali Iodide Solids by Swift Dust Particle Impact
Authors: Knabe W. , Krueger F. R. 
Published: February 2015

Abstract
Swift Fe-dust particles (0.2-20 μmØ ; 1-50 km/s) are utilized to generate transiently ions from alkali iodide coated metal foils, analyzed by time-of-flight mass spectrometry. By means of a thermodynamic treatment it is shown that simple heating by the impact cannot be hold responsible for the ion formation. However, this process is very much related to the non-adiabatic ion formation by pulsed laser irradiation. The damage caused by the impact particle resulting in cratering and thermal effects, which are long-term processes, is not related to the instantaneous ion formation.
Condensed Aromatics. Part XX. Coronene
Authors: Cyvin S. J. , Cyvin B. N. , Brunvoll J. , Whitmer J. C. , Klaeboe P. 
Published: February 2015

Abstract
The molecular vibrations of coronene, both in-plane and out-of-plane, are studied. The simple Hückel molecular orbitals are derived and the CC bond Oiders calculated. The bond orders are used to fix the CC stretching force constants. A complete set of independent symmetry coordinates is constructed. The in-plane vibrational frequencies are calculated by (a) the five-parameter approximation and (b) the Califano-Neto method; those of the out-of-plane vibrations only by the five-parameter approximation. The calculated frequencies are compared with observed values and previous calculations. A few new Raman bands are reported along with the presumably most complete set of infrared frequencies reported so far. A complete assignment of the infrared- active (E1u and A2u) fundamentals is proposed. A majority of the Raman-active frequencies (A1g, E1g and E2g) are also assigned, using Raman, fluorescence and phosphorescence spectra.
The Determination of Molecular Quantities from Measurements on Macroscopic Systems.II. The Determination of Electric Dipole Moments
Authors: Liptay Wolfgang , Becker Jürgen , Wehning Detlev , Lang Werner , Burkhard Oswald 
Published: February 2015

Abstract
Some bulk quantities appropriate for the description of dielectric and refractometric measurements on macroscopic systems are defined and their properties are discussed. Based on three molecular models (Lorentz model, Onsager model in spherical approximation, and in ellipsoidal approximation) model molar quantities are introduced, which depend on intrinsic properties of the molecule, i.e. the electric dipole moment and the polarizability. The relations will be applied for the evaluation of the results of dielectric and refractometric measurements on eight aromatic molecules.
The Determination of Molecular Quantities from Measurements on Macroscopic Systems.III. Electro-optical Absorption Measurements on Michler's Ketone
Authors: Liptay Wolfgang , Becker Jürgen 
Published: February 2015

Abstract
Some bulk quantities appropriate for the description of electro-optical absorption measurements on macroscopic systems are defined and their properties are discussed. Based on three molecular models (Lorentz model, Onsager model in spherical approximation and in ellipsoidal approximation) model molar quantities are introduced, which depend on intrinsic properties of the molecule (dipole moments and polarizabilities in the ground and excited state, transition dipole moment and transition polarizability). The relations will be applied for the evaluation of the results of electro-optical absorption measurements on Michler's ketone in cyclohexane in a wavenumber interval near 30 · 105 m-1 . The angles between the dipole moments in the ground and the excited state and the transition dipole moment will be determined; the magnitude of the dipole moment in the corresponding excited state is μaG = 30 · 10-30 Cm. The data show that the symmetry of a solute Michler's ketone molecule most probably corresponds, at least approximately, to the pointgroup Cs.
The Determination of Molecular Quantities from Measurements on Macroscopic Systems.V. Existence and Properties of 1:1 and 2:1-Electron-Donor-Acceptor Complexes of Hexamethylbenzene with Tetracyanoethylene
Authors: Liptay Wolfgang , Rehm Torsten , Wehning Detlev , Schanne Lothar , Baumann Wolfram , Lang Werner 
Published: February 2015

Abstract
The formation of electron-donor-acceptor complexes of hexamethylbenzene (HMB) with tetracyanoethylene (TCNE) was investigated by measurements of the optical absorptions, the densities, the permittivities and the electro-optical absorptions of solutions in CCl4. The careful evaluation of data based on some previously reported models, has shown that the assumption of the formation of the 1: 1 and the 2 : 1 complex agrees with all experimental data, but that the assumption of the formation of only the 1: 1 complex is contradictory to experimental facts even if the activity effects on the equilibrium constant and of the solvent dependences of observed molar quantities are taken into account. The evaluation leads to the molar optical absorption coefficients and the molar volumes of both complexes and to their electric dipole moments in the electronic ground state and the considered excited state. According to these results the complexes are of the sandwich type HMB-TCNE and HMB-TCNE-HMB. In spite of the fact that the 2: 1 complex owns a center of symmetry, at least approximately, there is a rather large electric dipole moment in its excited state. Furthermore, values for the equilibrium constants and for the standard reaction enthalpies of both complex formation reactions are estimated from experimental data.
Zum Tieftemperaturverhalten von Na3NO3
Authors: Jansen Martin 
Published: February 2015

Abstract
Low temperature Guinier photographs of Na3NO3 ( + 20° → - 140 °C) indicate two phase transitions to M-Na3NO3 and T-Na3NO3 at - 53±3°C and - 122±3°C, respectively. During the phase transitions the main structural features (NO2-[ONa3]: antiperovskite type of structure) remain unchanged. The dynamically disordered NO2- in H-Na3NO3 order to form an antiferroelectric arrangement in T-Na3NO3. Crystal structures for M-Na3NO3 and T-Na3NO3 are proposed.
Exzeßenthalpien des Systems MgJ2 · 8 H2O/Äthanol
Authors: Christahl M. , Peschel W. 
Published: February 2015

Abstract
For the binary system MgJ2 · 8H2O/ethanol the integral enthalpies of mixing are experimentally determined. The mixing is exothermic, with an excess enthalpy increasing with salt concentration and reaction temperature as well. From the mathematical approximation of experimental data the differential enthalpies of solution and of dilution are obtained. It is concluded that the coordinated water molecules can only hardly be replaced by ethanol molecules.
Melting Behavior of Hydrocarbon Chain Molecules with Ionic End:Groups: Primary n-Alkylammonium Halides
Authors: Busico V. , Scopa A. , Vacatello M. 
Published: February 2015

Abstract
Stepwise melting behavior for a series of primary long chain n-alkylammonium chlorides was pointed out. A plastic phase, a smectic mesophase and a “clear” liquid possibly unisotropic were observed. The same trend seems to be common to other hydrocarbon molecules with ionic endgroups, including alkali metal n-alkanoates.
Studies of the EPR Parameters and the Local Tetragonal Distortion of V4+-Doped SrTiO3 Crystal
Authors: Zheng Wen-Chen , Fan Ying-Juan , Wu Xiao-Xuan 
Published: February 2015

The EPR parameters (g factors g||, g⊥ and hyperfine structure constants A||, A⊥) of V4+ ion in the tetragonal phase of SrTiO3 crystal were studied by high-order perturbation formulas based on a two-spin-orbit-parameter model, where the contributions from the spin-orbit-coupling-parameter of central 3dn ion and that of ligands are considered. It is found that the oxygen octahedron surrounding
the impurity ion V4+ changes from elongation along the tetragonal axis in the pure crystal to compression and the magnitude of tetragonal distortion of oxygen octahedron (characterized by |ΔR|=|R||−R⊥|) inV4+ center is much greater than the corresponding value in the pure crystal. The cause related to the strong Jahn-Teller effect is discussed.
Zu den Phasenbeziehungen im System V/Nb/O, IV. Die Festelektrolyt-Coulometrie (FEC) als Methode zur Aufklärung ternärer Zustandsgebiete am Beispiel des Systems V/Nb/O/The Phase Relations in the System V/Nb/O, IV. Solid Electrolytic Coulometry (SEC) as a Method to Investigate Ternary Systems: V/Nb/O
Authors: Kirsten L. , Woedtke F. von , Oppermann H. 
Published: February 2015

The observation of reductive decomposition with SEC-current-time-temperature curves on the binary line V2O5-Nb2O5 is a useful method to determine qualitatively and quantitatively (“quasi in situ”) the known ternary coexistence regions. By reduction of VO2 the Magneli-Phases VnO2n-1 are generated. The method is generally applicable and allows rapid information by reductive decompositon or oxidative formation in coexistence regions.
The conditions of decomposition can be optimized for a given system. Slow solid-gas equilibria are not detectable by this method.