bluuebunny/crossref_metadata_2025 huggingface dataset:
Structure of Stark Broadened Hβ Lines at low Electron Densities
Authors: Ramette J. , Drawin H. W.
Published: February 2015

The profile of the hydrogen Hβ line emitted by a hydrogen low-temperature afterglow plasma has been measured at electron densities 1.8·1015 , 1·1015 and 5·1014 cm-3 by means of a 10-channel analyzer system with a spectral resolution of 0.1 Å. All profiles showed weak plasma satellites suddenly appearing at wavelength distances which correspond to the electron plasma frequency and showing “satellite line wings” which slowly smooth out at larger wavelength distances. In the line core-where all quasi-static and ion dynamic theories predict a minimum - appeared an intensity maximum well separated from the closely spaced intensity shoulders. This new feature not yet predicted by line broadening theories and not yet observed by other experimentalists is probably due to low-frequency ion oscillations which couple with the excited atomic system. Such an effect would explain discrepancies between available Stark broadening theories and the mass-dependent structure of line profiles recently observed in other experiments. The effect may possibly be useful for measuring collective low-frequency oscillations in plasmas under very special conditions.
A Molecular Dynamics Study of Aqueous Solutions
Authors: Heinzinger K. , Vogel P. C.
Published: February 2015

Results of a molecular dynamics study of aqueous solutions of LiJ, LiCl, NaCl, CsCl and CsF are reported. The basic periodic box contained 200 water molecules, 8 cations and 8 anions, equivalent to 2.2 molal solutions. Static properties of the first hydration shells of the ions are discussed in detail on the basis of radial pair correlation functions, average potential energies of the water molecules and pair interaction energy distributions. The calculations lead to the conclusion that in the first hydration shells a lone pair orbital of the water molecule is directed towards the cation while a hydrogen atom points towards the anion. In the five alkali halide solutions investigated ion pairing occurs only with CsF. The hydration numbers, when defined as the volume integrals of the ion-water radial pair correlation functions up to the first minimum, increase with increasing ion size and depend on the size of the counterion. The water-water interactions in the solutions show not only features of pure water at elevated temperatures but also of pure water under compresion. The agreement between calculated and measured self diffusion coefficients is still insufficient.
Time Resolved Magnetic Field Effects as a Probe for Geminate Recombination
Authors: Haberkorn R. , Midiel-Beyerle M. E.
Published: February 2015

A theoretical description for the magnetic field dependence of geminate recombination as observed in transient spectroscopy of electron transfer reactions, is given and applications of this novel magnetic field effect are discussed.
On Hypermomentum in General Relativity II. The Geometry of Spacetime
Authors: Hehl Friedrich W. , Kerlick G. David , Heyde Paul von der
Published: February 2015

In Part I** of this series we have introduced the new notion of hypermomentum Δijk as a dynamical quantity characterizing classical matter fields. In Part II, as a preparation for a general relativistic field theory, we look for a geometry of spacetime which will allow for the accomodation of hypermomentum into general relativity. A general linearly connected spacetime with a metric (L4, g) is shown to be the appropriate geometrical framework
On the Calculation of Nonlinear Spinor Field Functionals. III
Authors: Stumpf H.
Published: February 2015

The limitations of the Green functions method concerning nonlinear spinor theory are discussed. To remove these difficulties, functional quantum theory of the nonlinear spinor field was introduced in preceding papers. To obtain numerical values for the global observables in this theory, the functional eigenstates have to be calculated. In this paper especially for functional scattering states appropriate equations are derived. A general integration method of the spinor field functional equation is introduced, leading to an equation for the irreducible part of the state functional. Generating functionals are defined, allowing a separation of selfenergy and interactionenergy terms in the equation of the irreducible part. By spectral decomposition of the scattering functionals the boundary conditions are examined, which lead in connection with selfenergy and interactionenergy terms to the construction of channel equations for the irreducible part of elastic scattering functionals. The method is extented to inelastic processes, it can be tested in the case of nonrelativistic scattering theory. The procedure for the three particle case is discussed in some details
Theory of the Viscomagnetic Heat Flux
Authors: Vestner H.
Published: February 2015

The heat transport in the presence of a viscous flow and a magnetic field is studied for a rarefied polyatomic gas enclosed between infinite parallel plates. The total "viscomagnetic heat flux" is the sum of a bulk and a surface heat flux. According to moment equations of the Waldmann- Snider kinetic equation, the bulk heat flux is due to gradients of pressure (i. e. second order derivatives of flow velocity) and of tensor polarization. For the tensor polarization a second order differential equation is solved with boundary conditions obtained by Waldmann's thermodynamic method. This method also supplies an ansatz for the surface heat flux. In a thermally isolated box the viscomagnetic heat flux gives rise to a temperature gradient in y-direction if the magnetic field is in z-direction and the gas is flowing in x-direction. The bulk contributions to this transverse temperature gradient have already been given by Levi, McCourt and Beenakker. Now, the surface contributions and the total effect are studied quantitatively for some gases. In particular, it is discussed how a new surface parameter could be determined from future experimental data
On Ionization Equilibrium of Helium
Authors: Narain Udit , Jain N. K. , Chandra Suresh
Published: February 2015

The ionization equilibrium of helium is investigated using new ionization and modified dielectronic recombination rate coefficients. The results are discussed in the light of available data
Pressure Broadening of the 1.3 μm Iodine Laser Line
Authors: Fuß W. , Hohla K.
Published: February 2015

The storable energy of a high-power laser is inversely proportional to its stimulated emission cross-section σ. By adding a foreign gas, the emission line is broadened and is thereby lowered. We have measured σ of the iodine laser as a function of the pressure of several gases (Ar, N2, CO, CO2, SF6, CF3Br, C3F7I, CF2Cl2, (CF3)2CO) by an absolute and a relative method. 1/σ is a linear function of the pressure in spite of the fact that overlapping of the hyperfine structure components varies considerably in the range investigated. For optimum energy storage, CO2 is a good compromise between pressure broadening and chemical deactivation of the excited I-atoms. At one atmosphere of CO2, 5 to 7 J/cm-2 can be stored, the hyperfine structure is largely blurred, and the amplification of pulses shorter than 100 psec should be possible
Ab-initio Crystal Orbital Study of One-Dimensional Hydrogen Bonded Chain-Formic Acid
Authors: Kertesz M. , Koller J. , Zakrajšek E. , Ažman A.
Published: February 2015

Ab initio crystal orbital calculations on the β- and α-form are described. The binding energies and charge rearangement in hydrogen bonded chains are discussed
Three-Dimensional Electron Microscopy of Individual Biological Objects
Authors: Hoppe W. , Schramm H. J. , Sturm M. , Hunsmann N. , Gaßmann J.
Published: February 2015

In this paper methods and results of three-dimensional electron microscopy of individual molecules will be presented. Part I describes the general experimental and theoretical methods (microgoniometer, measuring scheme, two-dimensional and three-dimensional reconstruction, determination of the common origin of the projections). Special attention will be given to the image point shapes under different reconstruction conditions
Microwave Spectrum, Partial r0-Structure and 14N-Quadrupole Coupling Constants of 2-Cyanfurane
Authors: Engelbrecht L. , Sutter D. H.
Published: February 2015

The microwave spectrum of 2-Cyanfurane was investigated in the frequency range between 11 and 39 GHz. The rotational constants of the most abundant species indicate that the Cyano-group is bent toward the ring oxygen at the central C-atom. From the measured quadrupole coupling constants one may conclude that π-electron density is pulled from the ring toward the Nitrogen atom
Phosphoreszenzeigenschaften von Dibenzo-carbazolen und strukturanalogen Dinaphtho-thiophenen / Phosphorescence Properties of Dibenzo-carbazoles and Structure-related Dinaphtho-thiophenes
Authors: Zander M.
Published: February 2015

Phosphorescence spectra, lifetimes and quantum yield ratios of phosphorescence and fluorescence for carbazole, dibenzo- thiophene, three dibenzo-carbazoles and the corresponding dinaphthothiophenes have been measured in ethanol and in a heavy atom matrix at 77 K. Most of the results can be explained on the basis of spin-orbit coupling and term scheme concepts but an additional phosphorescencechemical structure relation is effective in these compounds
Depolarization of NaD2 Fluorescence under Pulsed Laser Excitation
Authors: Kroop V. , Behmenburg W.
Published: February 2015

The intensity and polarization state of the NaD2-fluorescence (3 2P3/2→3 2S1/2 , λ 5890 Å) from a cell containing pure Na vapor, selectively excited by a flash lamp pumped dye laser was investigated. Measurements were performed both for excitation with π-and σ-light of spectral density ranging between 10-23 and 10-17 Ws2 cm-3 and with Na number densities between 2.8 X109 and 4.0 X 1010 cm-3. The results are interpreted in terms of population of the 2P3/2 state and of hyperfine and Zeeman pumping of the 2S1/2 substates. The values for the degree of linear polarization measured at the smallest excitation densities and Na pressures agree well with theoretical values.
Chemical Oscillations by Substrate Inhibition
Authors: Seelig Friedrich Franz
Published: February 2015

The general reaction X+Y→P+Q, catalyzed by a metal M via M+X⇄MX and MX+Y→M+P+Q (or, in another subcase, MX+Y⇄MXY→M+P+Q) renders a chemical oscillator, if in an open system X and Y are supplied from appropriate sources by influxes j1 and j2, respectively, if X shows substrate inhibition by subtracting active catalyst by forming an inert complex MX2, and if at least X is limited by an additional first order side reaction. Introduction of dimensionless variables and parameters and assumption of a partial steady state for the catalyst compounds, the sum of wbich is constant, leads to 5 (or 6) parameters, 3 of which can be easily adjusted in a wide range. It is shown that for any given values of the 2 (or 3) fixed parameters the adjustable ones can in principle be chosen in such a way that the conditions for oscillation are met. This type of oscillator is thus a parametrically universal one. By appropriate choice of the adjustable parameters the yield of products can be conducted in bursts instead of a continuous flow. Another possibility is an excitable system that fires only on triggering. Proposals toward chemical realization are discussed especially with respect to transition metal complexes.
Equation of State and Thermodynamic Properties of Molten Potassium Chloride to 1320 K and 6 kbar
Authors: Goldmann G. , Tödheide K.
Published: February 2015

From the Tait equation an equation of state containing five adjustable parameters was developed which fits experimental density data of molten potassium chloride to 1320 K and 6 kbar with a standard deviation of 0.04%. The thermal expansion coefficient, isothermal compressibility, internal pressure, and molar heat capacities at constant pressure and constant volume were calculated as functions of pressure and temperature from the equation of state and were compared with computer simulation results. A method for an estimate of high-pressure PVT data for molten salts is suggested which yields results superior to the best computed data presently available.
Electronic Overlap Population as Reactivity Measure IV. Bond Cleavage and Bond Formation Processes
Authors: Sharafi-Ozeri S. , Muszkat L. , Muszkat K. A.
Published: February 2015

Electronic overlap population is explored as a reactivity measure for several bond cleavage and bond formation processes. The reactions considered include: I. decarboxylation of carboxylic acids and of their anions; II. carbon-hydrogen bond cleavage in γ-radiolysis of glutaric, methyl-malonic and 3-hexendioic acids; and, III. hydrogen atom addition to butadiene and to sorbic acid.
Radial Poiseuille Flow of a Homeotropic Nematic LC Layer
Authors: Hiltrop Karl , Fischer Fred
Published: February 2015

A two-dimensional Poiseuille flow in a radial direction allows to study simultaneously a whole range of flow rates. Three different deformation modes of the director field have been observed, the 'bow' mode, the 'screw' mode, and the 'peak' mode. Above a critical flow rate the bow mode transforms into the screw mode. Right and left screw mode can be produced side by side. The peak mode reached by temporary high flow rates is metastable at low flow rates. Quantitative results are reported and discussed.

By reversing the flow direction in the screw mode region the left screw mode is transformed into the right screw mode and vice versa.

By reversing the flow direction in the peak mode region special tube-like deformation structures are obtained. Each open tube has a point disclination at either end. Both are of opposite strength ± 1.
Scattering of a Polarized Photon by a Polarized Electron
Authors: Ewald H. , Franz W.
Published: February 2015

The scattering of a polarized photon by a polarized free electron is completely calculated in covariant form using Clifford's alternating vector algebra. The result is compared with several special results of the existing literature.
The T-t Jahn-Teller System: Solution of the Fundamental Combinatorial Problem and its Application to Moments and Zero Phonon Line
Authors: Sigmund E.
Published: February 2015

The solution of the T-t fundamental combinatorial problem is given in a purely analytic form as a sum over binomials. This simplifies other calculations considerably. For an illustration the moments of the optical absorption line shape in the strong coupling limit are derived in a closed form. Furtheron, the optical zero phonon line is calculated. An application to a T - t phase transition chain is indicated.
Stable and Metastable Phases in the Systems AgI-Ag2XO4 (X=Cr, Mo, W)
Authors: Magistris Aldo , Chiodelli Gaetano , Campari Giuseppina Viganò
Published: February 2015

DTA and powder x-ray diffraction measurements allowed to draw the phase diagrams of the systems AgI-Ag2XO4 (X = Cr, Mo, W).

A more detailed investigation was devoted to the composition range around XAgI = 0.8, where in preliminary tests it was observed that the room temperature ionic conductivity strongly depends on the thermal treatment of the sample.

By quenching mixtures at XAgI = 0.8, glass-like phases with high conductivity were obtained; in the systems AgI-Ag2CrO4 and AgI-Ag2MO4 the subsequent crystallization gave rise to non con-ducting phases, whereas the occurrence of the highly conducting compound 4AgI·Ag2WO4 was recognized in the third system investigated.
Photochemisches Verhalten und spektroskopische Eigenschaften von Anilino-naphthalinen
Authors: Fratev F. , Polansky O.E. , Zander M.
Published: February 2015

From the fluorescence and phosphorescence spectra of several aromatic amines it is concluded that the conjugation between nitrogen and aryl groups in the excited state is restricted. With this result a sterical explanation for the lack of the expected photochemical carbazole ring closure of 1-and 2-anilino naphthalene is given.
Fokker-Planck-Equation Approach to Flow Alignment in Liquid Crystals
Authors: Hess Siegfried
Published: February 2015

A nonlinear inhomogeneous relaxation equation for the alignment tensor is derived from a Fokker-Planck-equation for the orientational distribution function where torques exerted by a molecular field and by the gradient of the flow velocity are taken into account. Phenomenological coefficients characterizing the flow alignment in the isotropic and in the nematic phases are related to molecular parameters.
A Molecular Dynamics Study of Aqueous Solutions V. Angular Distribution of the Water Dipoles in the Hydration Shells of Various Alkali-and Halide Ions
Authors: Heinzinger K.
Published: February 2015

The angular distributions of the water dipoles have been calculated from molecular dynamics runs for the first hydration shells of various ions in 2.2 molal LiJ, LiCl, NaCl, CsCl and CsF solutions and in a 0.55 molal NaCl solution. It is shown how the distributions depend on the size of the shell taken around each ion. The results give no indication for the existence of desoriented water molecules in the immediate neighbourhood of the ions.
Resonanzverschiebungen in HF-Entladungen bei axialem Magnetfeld/Resonance Shifts in High Frequency Discharges in Axial Magnetic Field Configurations
Authors: Lammers B. , Oberlack U. , Schlüter H.
Published: February 2015

The pressure dependence of the lower hybrid resonance is investigated in a hydrogen plasma generated by a high frequency discharge. Appreciable shifts of the absorption peak with the neutral gas pressure are observed only in a mirror like magnetic field configuration. The measurements show that this shift cannot be explained by a change of the ion composition of the plasma, but must be attributed to two other mechanisms: The composition of the spectrum of the kn-components is influenced by the axial electron density profile so that at low pressure the higher modes of the spectrum are dominant.With higher pressure the formation of radial modes is favoured which leads to an additional apparent shift of the resonance.
Emittanz-Diagramme und Bildfehler von Elektronenkanonen
Authors: Lauer Rolf
Published: February 2015

The aberration coefficients of electron guns are determined from experimental shadow curves. For this purpose the curves are mathematically described by parametric equations using the ray inclination at the cathode as a parameter. Since the shape of the shadow curves depends strongly on the grid potential, different methods are required to adapt the calculated curves to the measured curves. Using the coefficients of the mathematical representation together with measured values for the magnification between cross-over and cathode, spherical and angular aberration are calculated with an accuracy of about 20%.
An I.R. Spectroscopic Study of the Conformational Equilibrium in 2-Acetylfuran
Authors: Paliani Giulio , Cataliotti Rosario , Poletti Antonio
Published: February 2015

The conformational cis/trans equilibrium of 2-Acetylfuran has been studied by i.r. spectroscopy, in various physical states. This equilibrium is strongly influenced by the dielectric constant of the medium. The isomeric energy difference is very small as revealed by the insensitivity of the equilibrium position to temperature changes.
Rotation -Torsion -Vibration Interaction in the Rotational Spectra of Isotopic Species of Ethyl Cyanide
Authors: Heise H. M. , Mäder H. , Dreizler H.
Published: February 2015

The measurements of the ground state rotational spectra of CH3CH2C15N and CH3CD2CN were extended to calculate the centrifugal distortion coefficients DJ , DJK and DK. The rotation-torsion-vibration interaction for these molecules including the normal species CH3CH2CN was studied in the rotational spectra of the first excited state of the methyl torsion and the CCN-in plane deformation. With respect to previous work a more detailed check of a model with five degrees of freedom comprising the overall rotation and the two lowest vibrations was possible. Potential parameters were fitted simultaneously to the splittings of the rotational transitions in the two lowest excited vibrational states of the three isotopic molecules. The coefficients V3 and V6 of the Fourier expansion of the hindering potential for the torsion and an interaction constant V'3c for the torsion and the CCN-in plane deformation were determined. Using these results it was possible to reproduce the frequencies of the torsional and CCN vibrations. With less success the torsional overtones could also be calculated.
Microwave Zeeman Spectrum, Electric Dipole Moment and Nuclear Quadrupole Tensor of Methyl Hypochlorite and d3 -Methyl Hypochlorite
Authors: Suzuki M. , Guarnieri A.
Published: February 2015

The microwave-Zeeman spectra of CH3O35Cl and CD3O35Cl have been investigated with magnetic fields up to 25 kG. In addition to the Zeeman parameters, the electric dipole moment and the chlorine nuclear quadrupole tensor have been determined.
Gleichgewichtseigenschaften von Ionenaustauschermembranen / Equilibrium Properties of Ion Exchange Membranes
Authors: Stormberg H.-P.
Published: February 2015

An electrolyte system in equilibrium is considered. The membrane acts on the ions by its electrostatic potential. Using a perturbation approximation in generalized Nernst Planck equations the densities are calculated for various electrolyte systems and various dielectric constants of the membrane.
Der Intensitätsverlauf im reinen Rotations-Raman-Spektrum von CO2 und N2O unter Berücksichtigung des 0110-Niveaus / Intensity Distribution in Pure Rotational Raman Spectra of CO2 and N2O Taking into Account Contributions from the 0110 State
Authors: Altmann K. , Klöckner W. , Strey G.
Published: February 2015

The pure rotational Raman spectra of carbon dioxide and nitrous oxide have been recorded with argon laser excitation and a resolution of about 0.2 cm-1. As was found previously for acetylene, also for these molecules R-branch transitions in the excited II-states could be resolved clearly up to J=9. The relative intensity distribution has been analyzed quantitatively according to formulae derived previously. It turns out that the experimental intensity distribution is well reproduced by taking into account only the

component of the anisotropic part of the polarizability tensor. Higher order contributions arising from the components

could not be detected.
Thermoreflectance in Ammonium Halides
Authors: Rieflin E. , Stühmer G. , Schwab E.
Published: February 2015

Thermoreflectance spectra of NH4I at 240 K, NH4Br at 93 K and NH4C1 at 160 K are measured. By a Kramers-Kronig analysis the differential optical dielectric constants are calculated to deter-mine band energies and their differential temperature behaviour. The spectra are compared with the excitonic spectra of the alkali halides, and the bands in NH4I are tentatively interpreted by analogy.
Electrochemical Transient Investigations of the Diffusion and Concentration of Electrons in Yttria Stabilized Zirconia-Solid Electrolytes
Authors: Weppner W.
Published: February 2015

The voltage relaxation of galvanic cells with zirconia electrolytes polarized between an inert silver electrode and an Fe + FeO electrode has been analyzed to obtain the diffusion coefficient of the electronic minority charge carriers in the temperature range between 700 and 900 °C. The method has been examined by using different thicknesses of the sample. At 800 °C the diffusion coefficient of the electrons is 1.4 × 10-3 cm2 /sec, i.e., about two orders of magnitude higher than that for the holes, 4.5 × 10-6 cm2/sec. The activation energy 0.55 eV is obtained for the electrons, compared to 1.4 eV for the holes. From conductivity data, the concentrations of electrons and holes at 800 °C and 1 atm oxygen partial pressure are calculated to be 1 × 109 and 4 × 1017 cm-3, respectively. The electronic band gap is evaluated to be 4.1 eV.
The Molecular Structures of HNC and HCN Derived from the Eight Stable Isotopic Species
Authors: Pearson E. F. , Creswell R. A. , Winnewisser M. , Winnewisser G.
Published: February 2015

Ground vibrational state rotational transitions have been measured for the following isotopic species of HNC: H15NC, H15N13C, DN13C, D15NC and D15N13C. Similar transitions have also been measured for H13C15N and D13C15N. These measurements complete the set of rotational constants for the eight stable isotopic species of the two molecules. Molecular structures are calculated from these data in several ways and are compared with the results of recent ab initio calculations.
Acetyl Cyanide II. Rotation–Torsion–Vibration Interaction in the Rotational Spectrum
Authors: Scappini F. , Mäder H. , Dreizler H.
Published: February 2015

The rotation-torsion-vibration interaction in acetyl cyanide, CH3COCN, has been studied in the rotational spectra of the first excited state of the methyl torsion and of the CCN-in-plane bending. A model with two internal degrees of freedom has been used to account for the A-E rotational splittings in the ground state and in the two excited states simultaneously. The constants in the Fourier expansion of the potential hindering the methyl torsion are determined. The results are compared with those obtained in a previous work from the A-E rotational splittings of the ground state only, using a model with one degree of freedom. Group theoretical considerations are made upon the Hamiltonian used in the present analysis.
Radialverteilung der Nachleuchte-Lichtintensität im Stickstoff / Radial Distribution of the Light-intensity in Nitrogen Afterglow
Authors: Kocian P.
Published: February 2015

Radial Distribution of the Light-intensity in Nitrogen Afterglow The radial distribution of the first positive band system in nitrogen afterglow in dependence on the discharge current and on the pressure has been investigated. The measurements were made in the pressure range 0.06 torr-6 torr. It has been found that the radial profile of the intensity fol-lows approximately the square of the J0 Bessel function.
Ionen-und Molekülbeweglichkeiten in einfachen binären Salzschmelzen / Ionic and Molecular Mobilities in Simple Binary Molten Salt Mixtures
Authors: Richter Joachim
Published: February 2015

For additive binary molten salt mixtures the ionic mobilities, the interdiffusion mobility and the self diffusion mobilities are defined. Values of these mobilities are given for the system NaNO3+AgNO3 at 290 °C in dependence of the composition.
Reciprocity and Boundary Conditions for Transport-Relaxation Equations
Authors: Waldmann L.
Published: February 2015

Recently a reciprocity theorem has been derived from the transport-relaxation equations for a simple system, consisting of one medium (Ref.1). With a composite system, consisting of two immiscible media in contact, a plausible generalized reciprocity scheme, here called universal reciprocity postulate, is suggested now. It leads to an equivalent reciprocity requirement at the inter-face between both media and thus decisively restricts - in form of provable Onsager relations - the possible constitutive laws connecting the thermodynamical forces and fluxes at the interface. For the formulation of these ideas, some mathematical tools are developed in advance. Finally, heat conduction is treated, as the most simple example, first in the direct way, then according to the more sophisticated mathematical tools.
Solitary Filaments of Coupled Electromagnetic Wave and Finite Amplitude Ion Fluctuations
Authors: Shukla P. K. , Yu M. Y. , Tagare S. G.
Published: February 2015

We show analytically that the nonlinear coupling of a large amplitude electromagnetic wave with finite amplitude ion fluctuations leads to filamentation. The latter consists of striations of the electromagnetic radiation trapped in depressions of the plasma density. The filamentation is found to be either standing or moving normal to the direction of the incoming radiation. Criteria for the existence of localized filaments are obtained. Small amplitude results are discussed.
Poisson's Ratio for Central-Force Polycrystals
Authors: Ledbetter H. M.
Published: February 2015

The Poisson ratio υ of a polycrystalline aggregate was calculated for both the face-centered cubic and the body-centered cubic cases. A general two-body central-force interatomatic potential was used. Deviations of υ from 0.25 were verified. A lower value of υ is predicted for the f.c.c. case than for the b.c.c. case. Observed values of υ for twenty-three cubic elements are discussed in terms of the predicted values. Effects of including volume-dependent electron-energy terms in the inter-atomic potential are discussed.
Electric Conductivity and Density of Sodium-Rubidium and Sodium-Cesium Acetate Molten Mixtures
Authors: Leonesi Dante , Cingolani Augusto , Berchiesi Gianfrancesco
Published: February 2015

The electric conductivities, densities and activation energies of RbC2H3O2 and CsC2H3O2 pure salts and (Na, Rb) C2H3O2 and (Na, Cs) C2H3O2 molten mixtures are reported. Deviations from addivity for the Vm , Λe and EΛ values are explained. The results for X2H3O2 where X=Na, K, Rb, Cs and for (Na, X) C2H3O2 , where X = K, Rb, Cs are discussed.
Konformationsuntersuchungen durch Elektronenspinresonanz Two-Jump-prozesse in Benzyl-phosphonium Salzen / Conformation Studies by Electron Spin Resonance Two-Jump Process in Benzyl-phosphonium Salts
Authors: Scheffler Klaus , Hieke Klaus , Schüler Paul , Stegmann Hartmut B.
Published: February 2015

The ESR spectra of 4-oxyl-benzyl-phosphonium-bromide radicals show a temperature dependence of the methylene protons and the phosphorus nucleus coupling constants which is explained by a hindered rotation of the phenoxyl ring of the radicals. Furthermore compounds with different phosphor substituents exhibit the phenomenon of a two jump process. This effect is described by an isomerisation of two symmetric radical conformations. Activation energies for this process are found to be around 7 kcal/Mol. The conformation of the radicals can be discussed as staggered ethane analogues. A lower limit value for the hyperconjugation Bᴾ -parameter is proposed.
Order Parameter Temperature Dependence of Some Nematic Liquids Related to Magnetic and Optical Anisotropies
Authors: Ibrahim I. H. , Haase W.
Published: February 2015

The diamagnetic susceptibilities, refractive indices and densities were measured as a function of temperature for three 4,4'-disubstituted benzoic acid-phenylester compounds. The polarizabilities were calculated using the Vuks formula and Neugebauer's relations. The orientational order parameters obtained from the magnetic and from the optical data as a function of temperature, in the absence of single crystal data, were compared.
Reaction of Vanadyl Ions with Alkyl Dinitriles
Authors: Al-Janabi Monther Y. , Ali Naseef J.
Published: February 2015

New complexes were prepared from the reaction of vanadyl ion with malononitrile and succinonitrile. Both complexes were found to exhibit a decrease in C ≡ N streatching frequency.

The reaction of vanadyl ion with malononitrile ion gives a complex in which the C ≡ N stretching frequency is increased. The increase or decrease is related to the type of bonding and to the difference in π-back bonding.
Untersuchung der elektrischen Leitfähigkeit homologer N-(4-n-Alkyloxybenzyliden)-4'-n-butylaniline im nematischen und smektischen Phasenbereich / Investigation of the Electrical Conductivity of Homologous N-(4-n-alkoxybenzylidene)-4'-nbutylanilines in the Nematic and Smectic Phases
Authors: Heppke G. , Schneider F. , Sterzl A.
Published: February 2015

Investigation The electrical conductivity of the first eight homologous N-(4-n-alkoxybenzylidene)-4'-n-butylanilines is investigated in the isotropic, nematic and smectic phases using the electrolyte tetra-butylammonium picrate. The anisotropy ratio of the electrical conductivity shows pretransition behaviour in the nematic phases close to the transition to the smectic phases. This behaviour be-comes more distinct with increasing alkyl chain length of the liquid crystals. In the nematic phase of 40·4 an anisotropy ratio of V = 0.55 is determined at the lowest electrolyte concentration. Values of about V=0.05 were found in the smectic phases of several homologues. In the nematic phase, an increase of the electrolyte concentration effects an increase of the anisotropy ratio. This effect is systematically enhanced with increasing alkyl chain length.
Investigation of the 1H Spin-Lattice Relaxation in Polycrystalline NH4ReO4 Induced by Mechanical Sample Rotation
Authors: Rager H.
Published: February 2015

Measurements of the proton spin-lattice relaxation time, T1 , in polycrystalline NH4ReO4 have shown that mechanical sample rotation in the static magnetic field reduces T1 for proton magnetic resonance frequencies within the range 30 - 42 MHz. The rotation induced proton spin-lattice relaxation times, T1
′, were measured at different Larmor frequencies, sample rotation frequencies, and temperatures. At room temperature T1
′ increases with increasing proton Larmor frequency. The dependence of T1
′ on sample rotation frequency and temperature is small. The "normal" proton T1 times were determined as a function of temperature at 30 and 42 MHz. From these measurements an average activation energy of 2.4 kcal/mole was obtained for the NH4
+ reorientation. The "normal" spin-lattice relaxation behavior was observed to be non-exponential at 30 MHz above 200 K and at 42 MHz above 260 K and is nearly independent on temperature above 300 K.
Influence of Electron Noise on Three-dimensional Image Reconstruction
Authors: Hegerl R. , Hoppe W.
Published: February 2015

A three-dimensional reconstruction requires the same integral dose as a conventional two-dimensional micrograph provided that the level of significance and the resolution are identical. The necessary dose D for one of the K projections in a reconstruction series is, therefore, the integral dose divided by K.
Schwingungseigenschaften des ReF6
+ -Ions
Authors: Baran Enrique J.
Published: February 2015

The principal force constants for ReF6
+ have been calculated using the GVFF. Mean amplitudes of vibration and bond orders are also estimated. The results are briefly discussed and some comparisons with related species are made.
Hyperfeinstruktur des RbJ / Hyperfine Structure of RbI
Authors: Tiemann E. , Hoeft J.
Published: February 2015

The quadrupole hyperfine structure of 85Rb127I in the ground vibrational state was measured on the rotational transition J = 3→4 at 7.9 GHz. From the observed spectra the following quadrupole coupling constants were derived: 85Rb : e q0 Q = -40.40(30) MHz; 127I : e q0 Q = -59.89(30) MHz.
Nachweis von atmosphärischem NO im ppb-Bereich mittels Fluoreszenzanregung durch NO-γ-Banden / An Optical Method to Monitor NO in Air, where NO Fluorescence is Excited by NO-γ Bands
Authors: Höinghaus K. , Biermann H. W. , Stuhl F.
Published: February 2015

An optical method to monitor NO in air and exhaust gas has been investigated. In this method NO is excited by NO-γ-bands (A2 Ʃ+ ← X2 IIr) generated in a microwave discharge and is detected by its subsequent fluorescence. Results indicate a linear detection range from 7.5 ppb to 1000 ppm in air using a time response of 10 s. Interferences from other atmospheric constituents are found to be small. The analysis requires only a small amount of sample gas.
Chaotic Behavior in Simple Reaction Systems
Authors: Rössler Otto E.
Published: February 2015

Deterministic nonperiodic flow (of “chaotic” or “strange” or “tumbling” type, respectively) was first observed, in a 3-component differential system, by E. N. Lorenz in 1963. A 3-component abstract reaction system showing the same qualitative behavior is indicated. It consists of (1) an ordinary 2-variable chemical oscillator and (2) an ordinary single-variable chemical hysteresis system. According to the same dual principle, many more analogous systems can be devised, no matter whether chemical, biochemical, biophysical, ecological, sociological, economic, or electronic in nature. Their dynamics are determined by the presence of a “folded” Poincaré map. Under numerical simulation, the proposed chemical system provides an almost ideal illustration to the underlying dynamical prototype, the “3-dimensional blender”. Thus, continuous Euklidean dynamics (and with it chemical kinetics) proves to be of equal interest in studying chaos as discrete dynamical systems already have.
Centrifugal Distortion Analysis of the Microwave and Millimeter Wave Spectra of Deuterated Ketenes1,2
Authors: Nemes László , Winnewisser Manfred
Published: February 2015

Measurements of R and Q branch a-type pure rotational transitions in the frequency range from 8 GHz to 220 GHz are reported for ketene-d1 and ketene-d2. The microwave and millimeter wave transitions were analysed in terms of Watson’s reduced Hamiltonian, including the sextic terms HKJ and HJK. The values of the inertial defect and the τ defect obtained from the centrifugal distortion analysis are in accord with the planar model for the ketene molecule.
Die Elektronenwärme von Legierungen des Systems MgCu2-MgNi2 / The Electronic Specific Heat in the System MgCu2 — MgNi2
Authors: Gnann Helmut , Eichenauer Walter
Published: February 2015

Measurements of the molar heat capacity in the quasi binary system MgCu2-MgNi2 from 1.5 to 4.2 K have been made in order to calculate the electronic specific heat. According to previous investigations in other alloy systems (Laves phases) the Sommerfeld model for free electrons does not hold. The shape of the electronic specific heat function versus alloy composition is comparable to that of the susceptibility and in poorer agreement with the hydrogen solubility. Iron impurities in some alloy samples caused an anomalous temperature dependence of the heat capacity.
Precision Measurement of γ-Ray Energies from the Decay of 57Co, 60Co, 137Cs, 152Eu, 153Sm and 198Au
Authors: Borchert G. L.
Published: February 2015

Energies of y-rays from the radioactive decay of 57Co, 60Co, 137Cs, 152Eu, 153Sm and 198Au have been measured relative to the 411.794 keV γ-ray standard from the decay of 198Au. The relative accuracy of the measurement is between 1.7 × 10-5 and 1.0 × 10-5 for Eγ<900 keV.
Zum Rotationsspektrum des InBr / On the Rotational Spectrum of InBr
Authors: Tiemann E. , Köhler U. , Hoeft J.
Published: February 2015

The hyperfine structure of the rotational transition J = 1→2 in the frequency range of 6.6 GHz was measured. The analysis yields the following quadrupole coupling constants:

eqvQ (115In) = [-634.62 + 2.52 (ν+1/2) ± 0.45] MHz,

eqvQ (79Br) = [110.38 + 0.50 (ν+1/2) ± 0.50] MHz,

eqvQ (81Br) = [91.88 + 0.45 (ν+1/2) ± 0.50] MHz.

The new determinations are consistent with the systematic trends of the III/VII diatomic molecules and remove the discrepancies of the older measurements of Barrett and Mandel1.
Formation of Periodic Ripples in a Surface Skin
Authors: Fischer Fred
Published: February 2015

A solid elastic skin on a liquid surface aquires a periodic ripple formation when a compressive strain surpasses a critical value. From a calculation the ripple wavelength is found to be proportional to the 3/4th power of the skin thickness. This instability can be described as a kind of second order phase transition, where a relative amplitude of the ripple wave is the order parameter. In addition, when the skin area is abruptly compressed the ripple wavelength depends on the magnitude of the compressive strain. Examples for skin rippling with wavelengths between 10 μm and 100 m are discussed.
Some Theoretical Considerations About the Excited Singlet and Triplet States of Diformamide and N-Methyl Diformamide
Authors: Marañon Julio , Sorarrain Oscar M.
Published: February 2015

The molecules of diformamide and N-methyl diformamide are analysed using the CNDO-CI method. Several excited singlet and triplet states corresponding to the three possible conformers and charge distributions are discussed.
Electrophilic Substitution Sites of Aromatic Compounds in Terms of Perturbation Theory
Authors: Janoschek Rudolf
Published: February 2015

Commencing from qualitative ah initio calculations on the molecules benzene, toluene and fluorobenzene, the corresponding favoured positions of electrophilic substitution are discussed in terms of perturbation theory including the electrostatic molecular potential and polarisation
The Electrical Resistivity of Exploding Ni-Wires in Fast RCL-Circuits
Authors: Seydel U. , Fucke W. , Möller B.
Published: February 2015

The electrical resistivity of Ni is derived from time-resolved measurements of current and voltage of exploding Ni-wires, which are part of a fast RCL-discharge circuit. The values of the resistivity at the Curie-point and at the melting point are in good agreement with stationary measurements. Deviations are discussed. Furthermore, the energy dependence of the resistivity of liquid Ni up to the boiling point (at normal conditions) is determined and compared with the temperature dependence assuming a constant specific heat
On the Mechanism of CaWO4 Formation in the Solid State from CaO and WO3
Authors: Flor Giorgio , Massarotti Vincenzo , Riccardi Riccardo
Published: February 2015

The formation in the solid state of CaWO4 from CaO (single crystal) or Ca3WO6 and WO3 was investigated by the contact method between 800 and 1000 °C in air and in argon.

The results obtained indicate that these reactions are governed by the diffusion of the W6+ and O2- ions.

From the CaWO4 structure, along with the lattice disorder predominant in this compound (0 vacancies and 0 interstitials) and the values of ionic mobilities, it was possible to state that the oxygen diffusion, via V0
2·, represents the rate - determining step in the considered reactions
Determination of Ionic Mobilities of Uranium in Aqueous Solutions at 25 °C by Use of Conductivities
Authors: Marx G. , Wittke W.-D.
Published: February 2015

In pure water the limiting ionic conductance of (½ UO2
2+) was found to be 57 cm2 Ω-1 mol-1 by use of conductivity measurements of UO2 (ClO4)2 • xH2O in diluted perchloric acid
Barrier Heights to Ion Migration in Alkali Halides
Authors: Uppal M. K. , Rao C. N. R.
Published: February 2015

Shell model calculations have been carried out to estimate the barrier heights to migration of ions in alkali halides by employing Sangster's parameters. The calculated values are in good agreement with experiment
Generalized Peierls-Boltzmann Transport Equations for Phonons and Local Excitation Kinetics
Authors: Kaiser Fr. , Wagner M.
Published: February 2015

The Peierls-Boltzmann transport equation for phonons is re-formulated and modified by means of sequences of transport and statistical postulates. The transition probabilities within the collision term are expanded in a comprehensive way. The resulting nonlinear kinetic equations are applied to a simple model system, i. e. a local excitation coupled to a transport system. The steady state solutions reveal the possibility of a hysteresis-type of "transport phase transitions" from the "thermo­ dynamic" branch to a "nonthermodynamic" one via a cumulative excitation. The stability of the solutions is checked and the approximations are discussed.
Isotope Effect of the Pure 35Cl and 37Cl Quadrupole Resonance Spectra in CHCl2COOH and CDCl2COOD
Authors: Rager Helmut , Wergin Alexander
Published: February 2015

The temperature dependence of the pure nuclear quadrupole resonance of 35Cl and 37Cl in solid CHCl2COOH and CDCl2COOD has been measured. The spectra are doublets according to two dif­ferent sites, Cl (I) and Cl (II), of the chlorine atoms in the CXCl2 group (X = H,D). In CHCl2COOH and CDCl2COOD the 37Cl spectra became unobservable above 198 K and 175 K and the 35Cl spectra vanished at 238 K and 226 K, respectively. The temperature dependence was calculated using the Bayer-Kushida theory which gives a satisfactory approach in the case of the compounds investigated here. A small difference has been found in the temperature dependence of the resonance frequen­ cies for CI (I) and CI (II) in both the CHCl2 and CDCl2 group, which is probably due to differences in the bond lengths of CI (I) and CI (II). Furthermore, there is a different temperature dependence of the resonance frequencies of the chlorine isotopes at the sites CI (I) and CI (II). This gives evi­ dence for the so-called isotope effect: i. e. there are slightly different thermal motions for the chlorine isotopes which are involved in the averaging of the electric field gradient tensor. The re­ placement of protons by deuterons gave a shift of the resonance frequencies of about 20 kHz to lower values. This may be primarily caused by effects of deuteration on the electronic structure.
Experimentelle und Quantenchemische Untersuchungen der Dipolmomente von Substituierten Stilbenen im Ersten Angercgten Singulettzustand / Experimental and Quantum Chemical Investigations of Dipole Moments of Substituted Stilbens in the First Excited Singlet State
Authors: Kawski A. , Gryczyński I.
Published: February 2015

The values a/a3 (α = polarizability), the Onsager cavity radii a and the dipole moments μe of six substituted stilbens in the fluorescent state have been determined. It is shown that if the dipole moment of the lowest excited singlet state μe is parallel to the dipole moment in the ground state μg, the values of μe and a can be determined from the solvent effects. Moreover, quantum chemical investigations of the dipole moments in the ground and excited states were carried out with the Pariser-Parr-Pople method and compared with the experimental values.
Periodic Ripples in a free Smectic A Surface Skin
Authors: Fischer Fred
Published: February 2015

A smectic A skin in a homeotropic texture on a liquid surface should form a periodic ripple when a horizontal compressive strain exceeds a critical value. The ripple wavelength is proportional to the fourth root of the skin thickness. In all practical cases the critical strain should be inversely proportional to the skin thickness. For a skin thickness approaching molecular dimensions, the critical strain has to be kept low by a small surface tension in order to avoid the formation of dislocations.
The Microwave Spectrum of Silylisothiocyanate, SiH3NCS
Authors: Dössel K.-F. , Sutter D. H.
Published: February 2015

The microwave spectra of 15N-and 13C-substituted SiH3NCS were recorded in the frequency region between 8 and 40 GHz. Combining the resulting rotational constants with values obtained previously for other isotopic species, the complete restructure of the heavy atom chain could be determined. This leads to the following rs-bond distances: rC-S = l-5745 Å, rN-C = 1.2208 Å, and rSi-N = 1.6725 Å. From Stark effect splittings the electric dipole moment of the most abun­dant species was determined for the ground vibrational state and for the first excited state of the lowest frequency bending vibration ν10 . The values are <ν10=0 | μz | ν10=0> = 2.38 + 0.02 D and <ν10=1, l=1| μz | ν10=1, l=1>=2.36 ±0.02D. The direction of the dipole moment is discussed. From the quadrupole hyperfinestructure of the J = 2→J′=3 rotational transition the 14N-quadrupole coupling constant could be determined as Xzz=0.75 MHz. The experimental results are compared to CNDO/2 calculations.
Influence of the Polarity of the Medium on the Alkaline Hydrolysis of n-Butyl Acetate in Hydroalcoholic Mixtures
Authors: Celdrán M. S. , Ramón M. V. , Martínez P.
Published: February 2015

The kinetics of the alkaline hydrolysis of n-butyl acetate have been studied in water and in hydroalcoholic mixtures. The rate constants, activation energies, frequency factors, entropies, Gibbs free energies and enthalpies of activation have been determined. The radii of the activated com­ plexes have been calculated and related to their degree of solvation. A possible reaction mechanism is formulated.
The Solid State Displacement Reaction CsCl + Nal → Csl + NaCl
Authors: Massarotti Vincenzo , Flor Giorgio , Riccardi Riccardo
Published: February 2015

The solid state reaction CsCl+Nal → CsI+NaCl was investigated, employing diffusion couples with two different contents of divalent cation impurities, in the temperature range 350-419 °C.

From kinetic determinations, inert marker experiments and X-ray diffraction analysis it was possible to deduce that the rate − determining step is the diffusion of I- in CsI via VI.