bluuebunny/crossref_metadata_2025 huggingface dataset:
Die Beeinflussung des Erwartungswertes 〈R-1〉für H-Atome durch die Zahl der verwendeten GTO-Basisfunktionen und deren Optimierung / The Dependence of the Expectation Value 〈R-1〉of H-atoms on the Number and Optimization of the GTO-functions
Authors: Sterk H. , Suschnigg J. J.
Published: February 2015

It has been shown that the number of GTO-functions on each H-atom has no remarkable in­ fluence on the expectation value 〈R-1〉- and therefore on the chemical shift - when the GTO-functions are energy optimized. An alteration of the GTO-functions leads to a fluctuation which is relatively insignificant if three s-functions are used for each H-atom.
Causality Violation and Non-local Generalization of the Lorentz-Dirac Equation
Authors: Alber P. , Heudorfer W. , Sorg M.
Published: February 2015

It is demonstrated by a concrete example (constant force of finite duration) that the recently proposed, non-local equation of motion for the radiating electron does exhibit the effect of causality violation. This phenomenon, which occurs in the non-local theory in form of self-oscillations, is however less severe than in the Lorentz-Dirac theory, if only physically reasonable forces are admitted.
The Anisotropy Function η(T) in Al-Cu and Al-Zn Alloys
Authors: Papastaikoudis Constantin
Published: February 2015

The anisotropy function η(T) for Al-Cu and Al-Zn alloys is determinated experimentally and compared with the theo­ retical results of Kagan and Zhernov.
Kinetic Modulational Instability of Upper-hybrid Turbulence
Authors: Shukla P. K. , Yu M. Y. , Tagare S. G.
Published: February 2015

It is shown that a plasma containing randomly distributed non-interacting upper-hybrid waves can become unstable against ion quasi-modes. The growth rate of the instability is presented.
The V-V Sector of the Lee Model
Authors: Petry Herbert Rainer , Sawicki Mikolaj
Published: February 2015

The Schrödinger-equation in the V-V sector of the Lee model is investigated. We obtain a three-body Lippmann-Schwinger equation, with a new type of disconnectedness, and construct the resolvent operator by means of a modified Faddeev technique.
Interaction of Antimalarials with Coenzyme Q10
Authors: Mammo Mareen , Shanshal Muthana
Published: February 2015

Assuming face to face (π-π) complexation of the antimalarials, quinine, primaquine and chloroquine, with CoQ and applying Hückel MOs for their quinoline skelet and for the dimethoxybenzoquinone ring of CoQ the interaction energies are calculated using 2nd order perturbation. The perturbation treatment yielded an increase in the LUMO energy of CoQ suggesting an increase in its reduction potential due to complexation. This increase is confirmed expermentally by Polarographic measurements of the E1/2 values for the corresponding 1:1 mixtures. Similar increase is observed for the 1: 1 mixture with aniline but not with cyclohexylamine. It is expected that such an increase in the reduction potential of CoQ should hinder its functioning as electron carrier in the respiratory chain.
Changes in Density of States Caused by Chemisorption: Monolayer of Adatoms on a Model Transition Metal
Authors: Masuda Kin-ichi
Published: February 2015

The effect of chemisorption of a monolayer of atoms on the (001) surface of a model transition metal is investigated using the Green's function formalism and the phase shift technique. The electronic structure of the surface is obtained by the application of the Kalkstein and Soven method. For comparison, both a single and two peaked model of the surface density of states (DOS) are used. The change in the DOS upon chemisorption as well as the adatom DOS are calculated within the Newns-Anderson model for chemisorption. It is shown that the two peaked substrate DOS model can qualitatively account for the strong coverage dependence of the photoemission spectra observed in the H/W(100) system. In addition, it is shown that the direct interaction between the adatoms plays an important role in the monolayer chemisorption.
Microwave Spectrum of Chloroacetylene in Ground and Excited Vibrational States
Authors: Jones Harold , Takami Michio , Sheridan John
Published: February 2015

The microwave spectrum of chloroacetylene in the ground and excited states has been investigated in the frequency range 15 to 306 GHz. Ground state rotational and nuclear quadrupole coupling constants for twelve isotopic species of chloroacetylene and accurate distortion constants were determined for two of these. The data allowed the rs-structure of chloroacetylene to be reconsidered and the internal consistency of this method of structure determination to be checked. Rotational spectra in five vibrationally excited states, with energy up to 700 cm-1 were observed for four different isotopic species and spectroscopic constants for these states were derived.
Voraussage der Temperaturabhängigkeit des Zusatzvolumens einfacher binärer nichtassoziierter Mischungen aus Reinstoffdaten / Predction of the Temperature Depedence of the Excess Volume of Simple Binary Nonassociated Mixtures from Data of the Pure Components
Authors: Liebermann Ernst
Published: February 2015

An equation relating the temperature dependence of the excess volume VE of simple binary liquid nonassociated mixtures to the molar volumes, the isobaric expansivities and the isothermal compressibilities of the pure solvents is proposed. The treatment is based on averaging over the macroscopic properties of the unmixed components on the grounds of classical thermodynamics. Predictions are made without using any empirical parameter.
Viscosity of a Polar Gas of Symmetric Top Molecules in Perpendicular Electric and Magnetic Fields
Authors: Köhler W. E.
Published: February 2015

A kinetic theory treatment of the influence of perpendicular magnetic and electric fields on the viscosity is given for a polar gas of symmetric top molecules. Expressions for the 9 independent viscosity coefficients are derived. In particular, the electric field influence on the transverse viscomagnetic pressure difference is studied.
Zur Messung von negativen Soret-Koeffizienten / Soret Coefficients of Negative Sign
Authors: Korsching H.
Published: February 2015

A cell with a small lateral dimension of 0.7 mm is constructed in order to avoid the possibility of disturbing convection. The temperature gradient can be set up downwards or upwards. A positive sign results for KCl in water but LiJ has a negative Soret coefficient, which is measured up to a molality of four at 25 °C.
Multiple Fluorescence of 7-Hydroxylepidone
Authors: Wolfbeis Otto S. , Lippert E.
Published: February 2015

The fluorescence spectra of the title compound have been measured in ethanol and in aqueous solutions of different pH. In ethanol the neutral molecule's fluorescence (at 360 nm) is observed, whereas in aqueous solutions emission occurs from the anion (at 428 nm) and from a "tautomeric" species (at 460 nm), but not from the neutral molecule. An aqueous solution at pH 3, which contains about 30% of ethanol gives a broad fluorescence band ranging from the near uv to the orange region of the spectrum. Contrarily, 7-methoxylepidone has no fluorescence maximum in the visible part of the spectrum.
Molecular Complexes of Macrocyclic Polyethers with Fluoranil
Authors: Jayathirtha Y. , Krishnan V.
Published: February 2015

Fluoranil forms weak 1:1 molecular complexes with both benzene substituted and nonbenzenoid macrocyclic ethers. 19FMR shifts have been used for the evaluation of association constants. The infrared and 1HMR data of the complexes reveal relative orientations of the molecules in the complexes.
Axial Channeling in Electron Diffraction
Authors: Ichimiya A. , Lehmpfuhl G.
Published: February 2015

Kossel patterns from Silicon and Niobium were obtained with a convergent electron beam. An intensity maximum in the direction of the zone axes [001] and [111] of Nb was interpreted as axial channeling. The intensity distribution in Kossel patterns was calculated by means of the Bloch wave picture of the dynamical theory of electron diffraction. Particularly zone axis patterns were calculated for different substance-energy combinations and they were compared with experimental observations. The intensity distribution in the calculated Kossel patterns was very sensitive to the model of absorption and it was found that a treatment of the absorption close to the model of Humphreys and Hirsch [Phil. Mag. 18, 115 (1968)] gave the best agreement with the experimental observations. Furthermore it is shown which Bloch waves are important for the intensity distribution in the Kossel patterns, how they are absorbed and how they change with energy.
Superstructures on Spherical Gold Crystals
Authors: Melle H. , Menzel E.
Published: February 2015

Spherically shaped crystals of gold were grown by solidification of a drop of melt in UHV. Their surfaces were investigated in situ by RHEED. The superstructures (001) (5 × 20) and (110) (1 × 2) were observed again. Further superstructures were found: on (001) vicinal planes, (227) (1 × 1), (111) (23 × 1) and (551)c(1 × 1). Several of the new structures are related to structures already known.
Steric Interaction of Fluid Membranes in Multilayer Systems
Authors: Helfrich W.
Published: February 2015

The out-of-plane fluctuations of fluid membranes are sterically hindered in multilayer systems. The repulsive interaction associated with the steric or excluded-volume effect is studied theoretically by two methods. The interaction energy per unit area of membrane is derived as a function of temperature, membrane curvature elasticity and mean membrane spacing; it is inversely proportional to the square of the latter. Steric repulsion is estimated for lecithin bilayers in water. There and in other cases, it may compete with van der Waals attraction.
Analysis of X-ray Diffraction Line Broadening using a Non-ideal Standard Specimen
Authors: Keijser Th. H. de , Mittemeijer E. J.
Published: February 2015

In practice a standard specimen used for the elimination of instrumental broadening, by deconvolution, is never ideal. The instrumental line profile always contains some additional broadening due to finite particle size and distortion present in the standard specimen. Further it is sometimes unavoidable to use a standard specimen of a material different from the material to be analyzed, leading to reflections at incorrect sin θ-values (different spectral broadening). Firstly the effect of these deficiencies on the Fourier coefficients of the pure line profile is analyzed. Secondly the consequences for size-strain analysis are considered.

A correction [Eq. (3.4) ] for the difference in spectral broadening between the exact and the approximate instrumental line profile is given. To avoid serious errors, this correction should be performed before particle size and strain are determined according to the so-called Warren- Averbach analysis. Accurate relative determinations of size and strain are possible even in the case that the line profile under investigation and the line profile of the reference specimen are at different sin θ-values. It is suggested that standard specimens which cause noticeable structural broadening can be used profitably.
Ab-Initio and PCILO Calculations of Diamond Clusters and the Corresponding Saturated Hydrocarbons
Authors: Waschi H. P. , Stoll H. , Preuß H.
Published: February 2015

Closed-shell diamond clusters and saturated hydrocarbons are investigated with PCILO and ab-initio Hartree-Fock using very small basis sets. The ab-initio distances for the C-C bonds differ by 5% or less, the PCILO distances by 2 to 2.5% from experimental data. The dependence of bond lengths and force constants on the cluster construction is studied. For selected molecules the effect of intermolecular rotations on the total energy is considered.
Einflüsse para- und diamagnetischer Substanzen auf 1HT1-Relaxationszeiten von Alkoholen / Influences of Para- and Diamagnetic Substances on the 1HT1- Relaxation-time of Alcohols
Authors: Sterk H. , Kalcher J.
Published: February 2015

The homologous series of Alcohols from Butanol to Tetradecanol was investigated with para-and diamagnetic shift-reagents with regard to their influences on the 1H relaxation-times. For the protons of the OH-, the CH2-O-, and the (CH2)n-groups, with increasing distance from the shiftmolecule, a decreasing influence on the T1-relaxation times could be verified. The Methylgroups of the long-chained Alcohols show an inverse tendency which can be explained by paramagnetic and Dipole-Dipole-Interactions with neighbour-complexes.

The purely paramagnetic influence on the T1-relaxation times of the different protons may be obtained by subtracting the diamagnetic influence from the total.
Oxygen Isotope Effect on 31P NMR Spectra in the Phosphate Ion
Authors: Lutz O. , Nolle A. , Staschewski D.
Published: February 2015

By Fourier transform high resolution NMR spectroscopy the 31P signals of the phosphate species 31P16O4-n
18On
3- (n = 0, 1, 2, 3, 4) have been resolved in aqueous solutions of potassium phosphate. An isotope effect on the Larmor frequency of δ(31P) = (0.019 ± 0.002) to lower frequency was found for the substitution of a 18O atom for a 16O atom in the phosphate ion.
Erzeugung und Untersuchung des Cyclopentadienons mit der Methode der temperaturabhängigen Photoelektronenspektroskopie / Preparation and Investigation of Cyclopentadienone by Variable Temperature Photoelectron Spectroscopy (VTPES)
Authors: Eck Veit , Lauer Günther , Schweig Armin , Thiel Walter , Vermeer Hans
Published: February 2015

Using our VTPES technique cyclopentadienone is generated in the gas phase at 500-600 °C from the three different precursors cyclobutene-3,4-dicarboxylic acid anhydride, o-phenylene sulfite and o-benzoquinone and its PE spectrum is recorded. The PE spectrum and also the PE spectra of the various precursors as well as of the cyclopentadienone dimer are interpreted on the basis of our recently developed PERTCI method (i. e. performing large scale perturbation configuration interaction calculations in connection with selection procedures). The agreement between measured and calculated ionization potentials is good.
On the Interaction of a Weak-R Type Ionization Front and a Contact Discontinuity
Authors: Berry J. S.
Published: February 2015

A numerical solution is given to the problem of a weak R type ionization front approaching a contact discontinuity across which the density increases. During the interaction it is found that there are three possible configurations produced; the weak-R type ionization front becomes (a) weak-R type but slower for ρ1/ρ0 < 1.15, (b) strong-D type for 1.15 < ρ1/ρ0 < 3.4 or (c) weak-D type for ρ1/ρ0 > 3.4, where the original ionization front travels through a region of initial density go and across the contact discontinuity the density becomes ρ1. A fine spacial mesh length is chosen so that the structures of the resulting ionization fronts and shock waves may be identified clearly at any time.
Coherent Oscillations in Biological Systems II Limit Cycle Collapse and the Onset of Travelling Waves in Fröhlich's Brain Wave Model
Authors: Kaiser Fr.
Published: February 2015

A brief description of the model equations and their underlying physical basis is given. The space independent problem of a previous paper is extended to include diffusive processes. Travelling wave solutions are introduced, the stability of the steady states and the different bifurcation schemes are discussed. The collapse of the limit cycle, by means of an external stimulation or by internal constraints as well as the onset of propagating pulses is considered. Phase portraits are discussed in great detail. Correspondence between some approximated versions of the model equations and nervous pulse propagation equations is established. Furthermore, some suggestions for an experimental proof of the model are made.
Density, Viscosity and Dielectric Constant of Aqueous Solutions of Triglycine and Tetraglycine
Authors: Bonincontro A. , Cametti C. , Sesta B.
Published: February 2015

The density, viscosity, static dielectric constant and microwave dielectric loss of aqueous solutions of triglycine and tetraglycine have been studied at various temperatures from 0 to 60 °C.

A very similar electrostrictive effect is observed for triglycine and tetraglycine solutions, indicating a different conformational behaviour of the two peptides in solution. The density B-coefficients decrease with temperature and suggest solute-solvent interactions which are also supported by the viscosimetric results. The viscosity 5-coefficients are always positive and the sign of dB/dT indicates that the two peptides are structure-breaking molecules.

The dielectric data show the existence of extended hydration sheaths with a different thermal stability for the two peptide molecules. The dielectric relaxation times and the activation enthalpies for these processes are estimated.
Structure of the Molten 37 a/o Cu-63 a/o Sb Alloy Using the Isotopic Substitution Method in Neutron Diffraction
Authors: Knoll W. , Steeb S.
Published: February 2015

A neutron diffraction study of the eutectic Cu-Sb-melt containing 37 a/o Cu has been performed using isotopically enriched samples. The three partial structure factors describing the Cu-Cu, Cu-Sb, and Sb-Sb correlations have been determined as well as a second set of partial structure factors relating to the distance correlation of fluctuations in number density and concentration.

Unsmoothed total structure factors were used. By Fourier-transformation the corresponding pair correlation functions were obtained. A strong segregation tendency was found. Concentration fluctuations with a correlation length of 2.4 Å could be determined. From the Fourier-transform of SCC the product N̄1α1 was obtained confirming the segregation tendency. The distance of nearest Cu-Cu neighbours in the eutectic Cu-Sb melt was found to be smaller than in pure molten Cu, whereas the Sb-Sb distance is larger than in pure Sb.

According to Faber-Ziman theory the electrical resistivity was calculated and compared with experimental data.
Zur Bestimmung der Beweglichkeit und Gleichgewichtskonstanten komplexierter Ionen mittels Gegenstromionenwanderung / Determination of the Mobilities and Stability Constants of Complex Ions by Means of Counter current Ion Migration
Authors: Herrmann F. , Bilal B. A.
Published: February 2015

In a countercurrent ion migration process the ion of an element (e.g. a metal cation) can form various unstable complexes with the anion of the countercurrent electrolyte. The ion migrates then with an average mobility, which is a function of the mobilities and equilibrium constants of the equilibrated species. In order to hold a constant ionic strength and to establish various metal/ligand-ratios, a background ion must be mixed to the metal ion. In usual "statical" stationary distributions, in which neither the metal ion nor the background ion is transported, the ratio of the two can only be hold constant if their mobilities are very similar. This difficulty can be overcome if the background ion is transported with constant rate through a statical stationary distribution of the metal ion, and vice versa. The solution of the transport equation for such "dynamical" stationary distributions shows that the average mobility of the metal ion can be calculated if its concentrations in locally independent parts of the stationary distribution and in the overflow are measured. The mobilities and the equilibrium constants of the various complex species are then determined by means of known mathematical methods
Über die Gleichgewichtsverteilung von Ionen an Phasengrenzen / About the Distribution of Ions near a Phase-Boundary
Authors: West Gerhard
Published: February 2015

For ideal-diluted electrolytes the concentration and potential profiles are calculated and the consequences of the deviation from the limiting law are discussed
Mikrowellenspektren schwingungsangeregter Zustände und allgemeines Valenzkraftfeld von 12C32SF35Cl / Microwave Spectra of Some Vibrational Excited States of 12C32SF35Cl
Authors: Hamm R.
Published: February 2015

The microwave spectra of some vibrational excited states of CSFC1 were measured with a conventional stark modulation spectrometer. As the spectra of the upper two stretching vibrations could not be found for lack of intensity, the equilibrium structure which had been estimated using Kuchitsu's procedure could not yet be determined. Nevertheless a general internal force field of CSFC1 was obtained, using the inertial defects of the measured excited states in the fit program NCA in addition to vibration frequencies and centrifugal distortion constants. Moreover, from the determined anharmonic part of the rotation vibration interaction constants, linear relations between some cubic force constants were established
Turbulent Spatio-Temporal Dynamics in Reacting-Diffusing Systems: Results for a Soluble Model
Authors: Ortoleva P. , DelleDonne M.
Published: February 2015

A class of soluble three "species" reaction-diffusion type systems is presented Exact solutions are obtained which show turbulent spatio-temporal evolution All homogeneous evolution tends asymptotically toward an attractor which is shown to be a two layered two dimensional manifold in the three dimensional species space. Sustained aperiodic spatio-temporal solutions are also found.

By considering particular model systems we show that turbulent solutions may exit as finite amplitude instabilities or as bifurcations which are aperiodic arbitrarily close to the bifurcation point and hence do not arise as a transition starting out essentially periodically.

A perturbation scheme is used to show that d parameter families of spatio-temporal evolution are admitted by more general systems with attracting d dimensional manifolds in the homogeneous chemical kinetics
On the Validity of the Master Equation for Finite Closed Systems
Authors: Seeberg O.
Published: February 2015

Two equations for the macroscopic part W of the statistical operator are considered:

It follows from the physical equivalence of the solutions together with a stability assumption and the assumption that there is a time τ* after which also the derivatives of the solutions are equivalent, that τ* is the life-time of the kernel K and that

Conversely, the equivalence of the solutions follows from assumptions on the life-time of the kernel K together with a stability assumption and a smoothness assumption on the initial statistical operator W(0).
X-Ray Diffraction Profiles of Inhomogeneous Binary Solids
Authors: Schattschneider P. , Wagendristel A.
Published: February 2015

A general expression for x-ray interference profiles of a binary alloy showing crystals of different concentration and thus different lattice dimensions is deduced. This expression contains previously reported relations as special cases, which are discussed briefly. It is not restricted to systems of total solid solubility or cubic lattice.
Molecular Vibration Analysis of the TeCl4 Tetramer and Monomer and the SeCl4 Tetramer
Authors: Cyvin S. J. , Cyvin B. N. , Brockner W. , Demiray A. F.
Published: February 2015

The molecular vibrations of (TeCl4)4 and (SeCl4)4 are studied on the basis of a cubane-like Td model. Symmetry coordinates are produced by using the theory developed for tetrahedral complexes with trigonal ligands. Approximate vibrational frequencies are calculated from very simple four-parameter force fields and used as an aid in tentative assignments of observed frequencies from literature. Next the force fields are refined by adjustments to the observed frequencies assigned as fundamentals. Potential energy distribution terms and mean amplitudes of vibration are calculated. Finally the monomeric form of TeCl4 is analysed, mainly in order to show the frequency shifts on passing from the monomer to tetramer.
MINDO-FORCES Calculation of the Benzyl and Vinyl Radicals and the Reactions 1CH2 + H2 → CH4 and CH4
.+ → CH3
+ + H
Authors: Khalil Salim M. , Shanshal Muthana
Published: February 2015

The MINDO/3-F0RCES method is applied for the calculation of the 1CH2+H2 → CH4 reaction. The variation of geometry is carried out in such a manner as to allow for the deviation from the C2v symmetry along the H7 -CH2 reaction coordinate. The changes in the geometric parameters of the system during the reaction are followed. It is found that the transition state of the reaction corresponds to R = 1.8 Å and has a geometry closer to the reactants than the products. The calculated activation energy is 13.57 kcal/mol and the calculated reaction enthalpy 106.36 kcal/mol (118.9 kcal/mol exp.). Similar calculations for the CH4
.+ yield a D2d structure and a ⊿Hf value of 269.68 kcal/mol (274.0 kcal/mol exp.). The activation energy of the decomposition reaction CH4
.+ → CH3
+ + H· is 84.54 kcal/mol, the reaction enthalpy is 42.83 kcal/mol (38.10 kcal/mol exp.). Using both MINDO/2- and MINDO/3.FORCES a C2v geometry is calculated for the benzyl radical. The ⊿Hf values are 48.40 and 67.93 kcal/mol respectively. The latter calculation shows that the rotated perpendicular conformation of the methylene group is by 2 kcal/mol less stable than the planar one. The rotation transition state corresponds to the rotation angle 50°. The change in ithe geometric parameters during the rotation is followed. For he vinyl radical the MINDO/3-FORCES calculation yields a CCH angle of 151.1° and a Hf value of 69.8 kcal/mol (65 kcal/mol exp.).
The Lie Derivative, Invariance Conditions, and Physical Laws
Authors: Steeb W.-H.
Published: February 2015

The properties of the Lie derivative of a differential form with respect to a vector field are applied to some physical problems. In particular we study balance equations.
Viscomagnetic Heat Flux Experiments as a Test of Gas Kinetic Theory in the Burnett Regime
Authors: Eggermont G. E. J. , Hermans P. W. , Hermans L. J. F. , Knaap H. F. P. , Beenakker J. J. M.
Published: February 2015

In a rarefied polyatomic gas streaming through a rectangular channel, an external magnetic field produces a heat flux perpendicular to the flow direction. Experiments on this “viscom agnetic heat flux” have been performed for CO, N2, CH4 and HD at room temperature, with different orientations of the magnetic field. Such measurements enable one to separate the boundary layer contribution from the purely bulk contribution by means of the theory recently developed by Vestner. Very good agreement is found between the experimentally determined bulk contribution and the theoretical Burnett value for CO, N2 and CH4 , yet the behavior of HD is found to be anomalous.
Fluorescence Detection of Atmospheric SO2 Using Excitation by NO-γ-Bands
Authors: Michels F. , Zetzsch C. , Stuhl F.
Published: February 2015

A method previously applied for the detection of NO was modified to also monitor SO2. With this method SO2 is excited by NO-γ-bands (A2 Σ+→X2 IIr) and is detected by its subsequent fluorescence in the wavelength region from 300 to 400 nm. The results indicate a linear detection range from 4 ppb to 100 ppm in air using a time response of 100 s. The interferences from some atmospheric constituents were investigated.
Ballooning Modes in Three-dimensional MHD Equilibria with Shear
Authors: Correa-Restrepo D.
Published: February 2015

Stability with respect to ballooning modes in arbitrary, three-dimensional, ideal MHD equilibria with shear is studied. The destabilizing perturbations considered here have finite gradients along the field and are localized around a closed magnetic field line, the localization being weaker on the surface than transversally to it. This kind of localization allows the problem of stability to be reduced to the solution of a one-dimensional eigenvalue problem.
Remarks on the Statistical Significance of Cross- Correlation Functions
Authors: Hoppe W. , Hegerl R. , Guckenberger R.
Published: February 2015

It is shown that the theory of the statistical significance of crosscorrelation functions can be based on different approximations. The validity range of these approximations is discussed.
Some Aspects in Recombining Transient Nitrogen Plasmas Some Aspects in Recombining Transient Nitrogen Plasmas Some Aspects in Recombining Transient Nitrogen Plasmas Some Aspects in Recombining Transient Nitrogen Plasmas Some Aspects in Recombining Transient Nitrogen Plasmas Some Aspects in Recombining Transient Nitrogen Plasmas Some Aspects in Recombining Transient Nitrogen Plasmas Some Aspects in Recombining Transient Nitrogen Plasmas
Authors: Gorse C. , Cacciatore M. A. , Capitelli M.
Published: February 2015

The temporal evolution of the population densities of a monatomic Nitrogen plasma has been studied in the electron temperature range 0.5 eV ≦ kTe ≦ 1 eV and in the electron number density interval 1012 cm-3 ≦ ne ≦1014 cm-3 by solving a coupled system of m aster equations. The results show that the times necessary to achieve quasi-stationary conditions for the population densities can be as long as 10-5 sec. in the optically thick plasma, and two order of magnitude shorter in the optically thin case. The possibility of population inversions during the recombination of a completely ionized Nitrogen plasma (ne ≃ 1015 cm-3, kTe = 0.5 eV) is then shown.
Elektronenrückstreuraten leichter Elemente in Molièrescher Näherung / Electron Backscattering Rates of Light Elements in Molière Approximation
Authors: Lehmann H.
Published: February 2015

Electron backscattering rates of light elements (atomic number Z = 6, 13, 29) are evaluated for electron energies of E = 20···60 keV. The scattering amplitude in Moliere approximation is expanded as a series. The series elements are calculated in closed form with the aid of substitute functions. By comparison with the first Born approximation this yields correction factors of 1···1,25.
On the Chemically Induced Decay Constant Variation of Tc-99 m
Authors: Nagel M. , Brunner G. , Dostal K.-P. , Hartmann E. , Hinneburg D. , Kupsch H. , Pabst D. , Rigó A.
Published: February 2015

The chemical induced decay constant variations for some complex compounds of Tc-99 m were measured by means of a semidifferential approach, using the scintillation technique. The results are

λ(TcO4
-) - λ(TcCl6
2-) = (2.52±0.30) · 10-3 λ,

λ(TcCl6
2-) - λ(TcBr6
2-) = (-0.02±0.20) · 10-3 λ,

λ(TcCl6
2-) - λ (TcI6
2-) = (0.78 ± 0.41) · 10-3 λ,

λ(TcO4
-) - λ(TcI6
2-) = (3.30 ± 0.30) · 10-3 λ,

λ(TcO4
-) - λ(TcBr6
2-) = (2.50 ± 0.41) · 10-3 λ.

Theoretical estimations by means of atomic structure calculations show that TcO4
- should have the greatest decay constant among the compounds investigated, in accordance with the measured values, and that the decay constants of the octahedral complexes should follow the spectrochemical series, partly confirmed by the experiments.
Semiempirisches Punktladungsmodell zur Berechnung von Valenzkraftkonstanten / A Semiempirical Formula to Estimate Valence Force Constants
Authors: Kosmus W.
Published: February 2015

A semiempirical formula to estimate valence force constants is derived. Using CNDO data, it is possible to get much better results than from empirical rules. The application of a simple point charge model allows a discussion of chemical binding.
Zustandsdiagramme und röntgenographische Untersuchungen einiger induzierter smektischer Mischphasen / Phase Diagrams and X -R ay Studies of the Induced Smectic Phases of Liquid Crystal Mixtures
Authors: Engelen B. , Schneider F.
Published: February 2015

Phase diagrams of mixtures of terminal polar and terminal non-polar liquid crystals that exhibit smectic phases with very large ranges of stability are presented. X-ray studies show that the in­duced phases are of type SA, SB or SE. The determination of the layer thickness shows that the induced smectic phases are composed of monolayers, whereas the terminal polar components are composed of bilayers. A model for the formation of the induced smectic phases is proposed.
Conductivity of the Liquid System Water + Acetic Acid + Silver Acetate
Authors: Haase R. , Nasr H. Ben , Dücker K .-H .
Published: February 2015

We present and discuss experimental values of the electric conductivity (and of the density) for the liquid ternary system water + acetic acid + silver acetate at 25 °C. The results given here represent a selection from measurements on more than 200 compositions. The concepts of equivalent conductivity and of limiting values for infinite dilution in the ternary system are also dealt with briefly.
On Master Operators with Extremal Entropy Production
Authors: Seeberg O.
Published: February 2015

The master operators B which cause the entropy production dH/dt = - k-1 dS/dt to become extremal for fixed statistical operators W are constructed and discussed. There are boundaries of the set B of master operators, B = {B | Σ B2
vu = b} for which the problem is solvable yielding minimal entropy production, while no solution exists in the set B without any constraints. Operators with maximal entropy production must be extremal points of B.
Die Pauli-Gleichung mit Differentialoperatoren für den Spin/ The Pauli Equation with Differential Operators for the Spin
Authors: Kern Eberhard
Published: February 2015

The spin operator s = (ħ/2) σ in the Pauli equation fulfills the commutation relation of the angular momentum and leads to half-integer eigenvalues of the eigenfunctions for s. If one tries to express s by canonically conjugated operators Φ and π = (ħ/i) ∂/∂Φ the formal angular momentum term s = Φ X π fails because it leads only to whole-integer eigenvalues. However, the modification of this term in the form s = 1/2 {π + Φ(Φ π) + Φ X π} leads to the required result.

The eigenfunction system belonging to this differential operator s(Φ π) consists of (2s + 1) spin eigenfunctions ξm (Φ) which are given explicitly. They form a basis for the wave functions of a particle of spin s. Applying this formalism to particles with s = 1/2, agreement is reached with Pauli’s spin theory.

The function s(Φ π) follows from the theory of rotating rigid bodies. The continuous spinvariable Φ = ((Φx , Φy, Φz) can be interpreted classically as a “turning vector” which defines the orientation in space of a rigid body. Φ is the positioning coordinate of the rigid body or the spin coordinate of the particle in analogy to the cartesian coordinate x. The spin s is a vector fixed to the body.
Optical and Thermal Electron Transfer in KCl: Tl+ Crystals
Authors: Tsuboi Taiju
Published: February 2015

The absorption spectra of Tl2+ in KCl crystals have been measured from 77 to 300 K. Tl2+ gives rise to five absorption bands peaking at 1760, 860, 680, 460 and 233 nm. These oscillator strengths have been calculated. Optical excitation in the 460 nm band destroys the Tl2+ and Tl++ bands and produces the Tl0 bands. Thermal excitation of a crystal containing only Tl2
+ and Tl++ results in the simultaneous decay of Tl2
+ and Tl++.

It is concluded that electrons released from Tl2
+ by optical or thermal excitation are trapped at Tl+ and Tl++. A discussion is given on Tl2
+++: A Tl2
+++ which has an absorption band at 1075 nm is formed when a (Tl+)2 traps a positive hole of a nearby Cl2
-, whereas it is deformed when a Tl2
+++ traps an electron released from a Tl2
+ by optical excitation in the 460 nm band.
Einfluß des Präparationsverfahrens auf das Restwiderstandsverhältnis kleiner Niobkugeln/ The Influence of Preparation on the Residual Resistivity Ratio of Small Spherical Niobium Samples
Authors: Gärtner K. , Westphal M.
Published: February 2015

A technique for preparing spherical niobium samples of high purity is described. The preparation of tunneling junctions starts from such spheres. The influence of temperature gradients during a heat treatment on the sample purity is discussed.
Different Kinds of Chaotic Oscillations in the Belousov-Zhabotinskii Reaction
Authors: Wegmann Klaus , Rössler Otto E.
Published: February 2015

Following earlier evidence for chaotic time behaviour in the open flow continuous stirred Belousov-Zhabotinskii reaction based on a single measured observable, now two-dimensional phase plots are presented. The potential of a bromide ion sensitive electrode was plotted against the electrochemical potential. In the two-dimensional observation space obtained, both apparent limit cycle oscillations and apparent chaotic oscillations were observed. Of the latter, type 1 resembles a double-limit cycle system with fluctuation-triggered transitions between the two regimes (exogenous chaos); type 2 is analogous, but here the irregular transition between the two oscillatory regimes gives the impression of being, in principle, independent of exogenous noise. If so, this flow may be related to one of the chaotic flows with saddle point known (for example, the Lorenz attractor). Type 3, only observed as a transient so far, looks like a two-dimensional projection of screw type chaos, which is one of the simplest types of deterministic chaos. Type 4 corresponds either to a fluctuation-triggered monoflop (exogenous chaos) or to folded-strip (spiral) type chaos.
Hartree-Fock Approximation with Pseudowavefunctions
Authors: Szasz Levente
Published: February 2015

By the introduction of pseudopotentials the Hartee-Fock equations for all electrons of an atom or molecule are exactly transformed into equations yielding orbitals which are nonorthogonal to the lower lying states.
Notizen:Niederfrequente dielektrische Relaxation in Einkristallen von Rubidiumtetrasilberjodid/ Low-Frequency Dielectric Relaxation in Single Crystals of Rubidium Tetra Silver Iodide
Authors: Becker Stephan , Schön Günter
Published: February 2015

The low-frequency dielectric absorption of RbAg4l5 single crystals was found to have a maximum at about 1 kHz. It was tried to explain this by considering the occurrence of ordered regions of silver ions in the crystal structure, according to the domain model proposed by van Gool. Some aspects supporting this model are discussed.
Derivation of Phonon Assisted Auger Transition Probabilites in Semiconductors
Authors: Tröster Fritz
Published: February 2015

In this paper a theory developed by Stumpf [1] will be used in order to calculate Auger transition probabilities in semiconductors. The main feature of the calculations is the incorporation of the coupling of impurity electrons to the surrounding lattice by phonons, using dynamical electronic wave functions for impurity states. The final result is an expression for transition probabilities, describing multiphonon assisted Auger transitions in semiconductors.
Die Uran(IV)-Liganden Wechselwirkungen in den Paramagnetischen Tetra- und (Tris-Cyclopentadienyl) -Halogeniden / Uranium(IV)-ligand Interaction in Paramagnetic Tetra- and (Tris-cyclopentadienyl)-halides
Authors: Aderhold Clemens
Published: February 2015

The magnetic susceptibilities of the uranium tetrahalides and of the tris-cyclopentadienyluranium- halides were measured from 1 to 300 K by using a Faraday magnetic balance at six applied magnetic fields between 3.50 and 13.1 kOe.

It is found that these compounds do not obey a Curie-Weiß law. Their effective magnetic moments at room temperature show maximally 70% of the moment calculated for the free U4+-ion.

By taking into account spectroscopic data the experimental magnetic susceptibilities can be described by using a modified Van Vleck theory.
Structure of the Hel 43D, 3F-2 3P (λ = 447.15 nm, λ = 447.0 nm) Spectral Line Emitted from a Low-Pressure Linear Discharge
Authors: Drawin H. W. , Ramette J.
Published: February 2015

=

The line profile of the HeI line at λ447.15 nm has been measured during the ionisation phase and during the afterglow of a condensed low-pressure helium discharge by means of a 10-channel spectrum analyzer having a channel width of 0.1 Å. The temporal resolution was I.6 μs (e-folding time). The filling pressure ranged from one to twenty Torr. The same relative peak structure was observed during the plasma build-up phase and the afterglow, only the intensities of the peaks were different in the two cases. Our measured profiles are quite similar to those obtained under different experimental conditions by other authors who explained the structure as being due to Baranger-Mozer plasma satellites. In contrast to this we did not find any correlation between electron density and peak position, i.e. the interpretation as Baranger- Mozer plasma satellites has to be excluded. The wavelengths of a number of peaks agree well with already identified He2 molecular lines, and there are sufficient experimental indications to conclude that the prominent part of the satellite structure originates from He0 molecular transitions most of which have not yet been identified.
Microwave Spectrum of 1-Butene Oxide
Authors: Ljunggren S. O. , Mjöberg P. J. , Bäckvall J . E.
Published: February 2015

The microwave spectrum of 1-butene oxide in the gas phase has been studied in the frequency region 18.0-39.0 GHz. The spectrum observed arose from a rotamer with a dihedral H-C2-C3-C4 angle of 59° ± 1°. In addition to several Q-branch progressions the spectrum contained several long perpendicular RP and PR progressions. However, of the ground state lines, only the intermediate PR transitions showed internal rotation splittings that could be resolved to yield a barrier height of 3.02 kcal mol-1. The value derived from the line splittings of the first excited methyl torsional state was slightly higher (3.17 kcal mol-1) but must be regarded as being less reliable. The components of the dipole moment, the rotational constants, and the quartic and sextic centrifugal distortion coefficients for the ground state and three vibrationally excited states were determined.
Calculation of Separatrices in Multistable Chemical Reaction Systems
Authors: Denzel B. , Seelig F. F.
Published: February 2015

In multistable chemical reaction systems the space of variables is partitioned by separatrices into different cells which are the domains of attraction of the respective critical points. By numerically solving an initial value problem, which is based on the particular stability properties of separatrix manifolds, we achieve a direct approximation of the stability boundaries in the phase space. The method is principally applicable to nonlinear systems of any number of variables and, other than the direct method of Liapunov, also in regions of the phase space which are far from the critical points.
Anlagerung von Elektronen in Luft und in Gemischen aus O2 mit He, N2 und CO2 / Electron Attachment in Air and Mixtures of O2 with He, N2, and CO2
Authors: Grünberg R.
Published: February 2015

The attachment coefficient η for the formation of negative oxygen ions in low energy electron swarms was measured in dry air and in mixtures of oxygen with helium, nitrogen and carbon dioxide. The shift of the η/pO2-curves of the mixtures against those for pure oxygen are in good agreement with the Bloch-Bradbury theory and can be explained by the influence of the admixted gas on the mean electron energy and the electron energy distribution function. Deviations from the regularity η/p2
O2 = const, described in an earlier paper have been followed up in air at higher pressure and in O2-CO2 -mixtures with a high share of CO2.
Hyperfine Structure in the Rotational Spectrum of GaBr
Authors: Pfaffe S. , Tiemann E. , Hoeft J.
Published: February 2015

The hyperfine structure of the rotational transition J = 2 ← 1 in the vicinity of 9.8 GHz was measured. The analysis yielded the following quadrupole coupling constants:

e qv Q (79Br) = 105.78(34) + 0.92 (38) (ν + 1/2) MHz,

e qv Q (81Br) = 88.55(35) + 0.60(32) (ν + 1/2) MHz,

e qv Q (69Ga) = -86 .6 8(30) + 0.36 (24) (ν + 1/2) MHz,

e q0 Q (71Ga) = - 54.58 (25) MHz.

These results are consistent with systematic trends in the group of (III a/VII a)-compounds and remove some discrepencies in the literature.
Photo Conductivity of Liquid Tetramethylsilane
Authors: Schmidt W . F. , Döldissen W. , Hahn U. , Koch E. E.
Published: February 2015

Intrinsic photo conductivity of liquid tetramethylsilane was observed in the wave length region from 1100 to 1500 Å. The photo ionization threshold EL has been determined to be EL = 8.1 eV.
Empirische Beziehungen der Energie der para-Bande und der Topologie von kataanellierten aromatischen Kohlenwasserstoffen / Empirical Correlations between the Energy of the para Band and the Topology of kata-annellated Aromatic Hydrocarbons
Authors: Zander M.
Published: February 2015

The energy of the para band of various types of kataannellated aromatic hydrocarbons can be correlated with the total number of π electrons and the number of inherent π sextets. An empirical formula for the calculation of the energy of the para band is derived. The observed correlations are discussed on the basis of the free electron approach.
On the Evaluation of Transport Collision Frequencies II. An Approximating Method to Express the Temperature Dependence
Authors: Weinert Ulrich
Published: February 2015

The temperature dependence of the transport collision frequencies is discussed, provided they are given for one special reference temperature. An approximative procedure to express this dependence is elaborated using the definition of the transport collision frequencies as expansion coefficients.
Tables of Radiative Corrections to Pion Nucleon and Nucleon-Nucleon Scattering
Authors: Borie E.
Published: February 2015

The importance of radiative corrections to hadron scattering is discussed, and the relevant formulas presented in a somewhat simpler form than has been given previously. Tables are given to enable the experimentalist to estimate the numerical importance of the corrections, or evaluate them by interpolation.
Application of the Model Microfield Method to Stark Profiles of Alkali Metal Resonance Lines
Authors: Mazure A. , Nollez G.
Published: February 2015

Stark widths and shifts of alkali metal resonance lines are calculated by the model microfield method (MMM). The im pact results of Griem for the prevailing electronic broadening are recovered by the unified MMM. Both theories are in close agreement with recent experimental results. It is shown further that the shift values are very sensitive to the line strength values of the involved transitions. The reliability of the experimentally observed regularities through the alkali sequence is next discussed. On the basis of the MMM results these regularities can be understood in term s of the line strengths and frequencies of transitions from the main levels actually involved.
Ratios of Isotopic Frequencies Using HLFS Method
Authors: Ananthakrishnan T. R.
Published: February 2015

Simple expressions involving elements of the kinetic energy matrix are obtained for the ratios of isotopic frequencies in the case of vibrational species, of order two and three, associated with small molecules by employing the high and low frequency separation method and the product rule. The applicability of the method is indicated.
Appearance Potentials of Field Desorbed Silver Ions
Authors: Hummel E. , Domke M. , Block J. H.
Published: February 2015

The onset, eδ0, in the energy distribution of field desorbed silver ions (from Ag deposit on a W-tip) has been measured at T > 400 K. With increasing field strength (0.5 < 1010 V/m < F < 1·1010 V/m) or with decreasing temperature (800 K > T > 500 K)

eδ0 increases up to 1.5 eV. For a comparison with the eδ0-values, activation energies, Q, for field desorption have been determined from Arrhenius plots (0.5 eV < Q < 2 eV). Two different kinetic regimes (desorption and diffusion) were identified. For field desorption, the sum eδ0 + Q is constant, irrespective of F-values.

In the frame of "image hump" or "charge exchange" models, field dependent activation barriers are discussed. Temperature dependencies are related to (i) the Fermi distribution of the emitter, (ii) the distribution of F and (iii) the distribution of surface bond energies. Results are consistently explained in a three-dimensional model with directionally distinguished desorption steps.