bluuebunny/crossref_metadata_2025 huggingface dataset:
Orientiertes Aufwachsen von AgCl auf kugelförmigen Silberkristallen / Epitaxy of AgCl on Spherically Shaped Silver Crystals
Authors: Wilken R. , Menzel E.
Published: February 2015

Tarnish layers of AgCl were grown by reaction of HCl + Cl2 gas with silver at 20 °C. Eight different systems of epitaxy were observed in the characteristic crystallographic triangle of Ag by diffraction of 60 kV electrons. The area around the Ag(011)pole is covered with monocrystalline AgCl having a continuous tilt depending of the angular distance from Ag(011). All systems of epitaxy are characterized by a small misfit of distance between low indexed atomic chains in Ag and AgCl.
Assoziationskontinua der positiven Molekiilionen im Kern von Niederstromliehtbögen / Association Continua of the Positive Molecular Ions in the Core of Low Current Arcs
Authors: Mück G. , Popp H.-P.
Published: February 2015

Measurements on low current Cl2-, Br2-, J2-, and AlCl3-arcs show an intense continuous radiation in the visible and near infrared spectral range, which is interpreted as association continuum of the various molecular ions.
Bestimmung der Bildungsenthalpie von Nitroxychlorid (Chlornitrat, NO3Cl) als Beitrag zur Deutung der Kinetik des thermischen NO3Cl-Zerfalls in der Gasphase und in der Lösungsphase / Determination of the Enthalpy of Formation of nitroxy Chloride (Chlorine Nitrate, NO3Cl). A Contribution to the Interpretation of the Kinetics of the Thermal Decomposition of NO3Cl in the Gas Phase and in Solution
Authors: Knauth H.-D. , Martin H. , Stockmann W.
Published: February 2015

The dissociation energy values ⊿H0298(ClO- NO2) = 25.87 kcal mol-1 and ⊿H0
0(ClO-NO2),0 = 24.8 kcal mol-1 were derived from the standard enthalpy of formation of nitroxy chloride (NO3CI) ⊿Hf0 = 6.28 kcalmol-1 which has been determined from the reaction enthalpy of the gas phase reaction NOCI + NO3CI = 2 NO2 + Cl2. With the help of these data it was possible to show that in the thermal decomposition of NO3Cl, for which the overall reaction is NO3Cl = NO2 +½O2 + ½Cl2. at temperatures around 100 °C the equilibrium NO3Cl ⇄ NO2 + OCl is established. At the beginning of the reaction, there exists such a high OCl concentration that the decomposition occurs practically exclusively by the reactions

OCl + OCl + M ⇄Cl2O2 + M,

Cl2O2 + M → Cl2 + O2+M

and

OCl + OCl → Cl + OOCl,

the last of which is followed by Cl-consuming reaction steps, e.g. CI + NO3CI → NO3 + Cl2, apparently initiating chain reactions. The reaction step NO2 + NO3Cl → NO3 + NO2Cl, postulated from an investigation of the kinetics in a nono-polar inert solvent, and its daughter reactions probably occur for the gas phase reaction as well.
Boundary Conditions for the Macroscopic Slip Velocity on a Curved Wall
Authors: Lehmann V. , Mueller W. J. C.
Published: February 2015

Equations for the macroscopic slip velocity on curved walls are derived using the Chapman- Enskog solution of Boltzmann’s equation.
Knudsen Corrections for Flow Birefringence in Gases
Authors: Vestner H.
Published: February 2015

Differential equations and boundary conditions for the flow velocity and the tensor polarization are solved for a cylindrical Couette-flow apparatus in a magnetic field. The ensuing Knudsen corrections for flow birefringence in gases consist of two contributions: (i) the velocity gradient is reduced by slip of the gas at the walls, (ii) the tensor polarization itself is influenced by gas-wall collisions. As a result, flow birefringence decreases for low pressures. For the gases HD, N2 and CO the relevant surface parameters are already known from Knudsen corrections for the Senftleben- Beenakker effect of viscosity. Thus the explicit pressure dependence of flow birefringence can be predicted for these gases (for zero magnetic field) and for the apparatus used by Baas
An Investigation of the Molecules O2, CHCl3, c—C4F8, C7F14 and HBr by Electron Cyclotron Resonance (ECR) Technique at Energies ≤ 0.4 eV
Authors: Christodoulides A. A. , Schultes E. , Schumacher R. , Schindler R. N.
Published: February 2015

Preliminary experiments have shown that helium gas can be considered a good choice to be used in electron cyclotron resonance (ECR) studies, at the same time as a carrier gas and as a source of production of free electrons. An account of destruction of He metastable atoms present in the flowstream is given. Changes in the linewidth with or without the electron scavenger and thermalization of the electrons are discussed. The energy dependence for the electron attachment to the molecules O2, CHCl3, c-C4F8, C7F14, and HBr is investigated. The energy scale for electron attachment processes in relation to the input microwave power is established for He carrier gas. Such processes can be studied by employing the ECR technique from thermal energies up to 0.4 eV
Argon-36 from Neutron Capture on Chlorine in Nature
Authors: Sinclair D. E. , Manuel O. K.
Published: February 2015

Argon analysis on samples of sodalite from Dungannon, Ontario reveals an excess of 36Ar from neutron capture on 35Cl and excess 40Ar from the decay of 40K. These results indicate an average production rate of 5.6 X 102 atoms of 30Cl per year per gram of chlorine over the age of the mineral. 3.9 X 108 yrs. The surface residence time of chlorine-rich rocks may be determined from the amounts of 36Ar which accumulate during the time period of exposure to cosmic rays
Uberfiihrunsszahlen bei Elektrolvtsdunelzen / Transport Numbers in Ionic Melts
Authors: Haase R.
Published: February 2015

For an ionic melt, consisting of three ion constituents, the limiting values for infinite dilution of all the internal and effective transport numbers are calculated. The diagrams shown in an earlier paper, concerning LiNO3 + AgNO3 at 260 °C, are extended so to include the limiting behaviour of the effective transport numbers
Zur Nichtlinearität der NCO-Gruppe (MO-SCF-Berechnungen an Isocyanaten III) / The Nonlinearity of the NCO-Group (MO-SCF Calculations on Isocyanates III)
Authors: Rode Bernd M. , Kosmus Walter , Naehbaur Edgar
Published: February 2015

The nonlinearity of the NCO group, as to be calculated after the CNDO method and in agreement with some experimental data, has been investigated systematically. The energy values, calculated for different angles, show the nuclear repulsion energy to be the determining factor for the bent (trans-) configuration of these compounds. The extent of this angle cannot be explained with classical chemical characteristics. A significant correlation is found, however, with the electronic situation at the C-atom, whose net charge and covalent bonding are likewise influenced by the NCO angle.
Cross Sections for the Destruction of an Alignment in the Metastable 63P2-State of Hg by Collisions with H2, N2 and CO2
Authors: Baumann M. , Jacobson E. , Koch W.
Published: February 2015

The cross sections for destruction of an alignment in the metastable 6 3P2-state of mercury atoms by collisions with H2, N2 and CO2 molecules have been determined from the observation of transient signals. The results were (in units of 10-16 cm2) H2: 63(7); N2: 104(13); CO2: 663(68).
Elektrische Leitfähigkeit und Strahlung eines Argonplasmas im Nachleuchten
Authors: Hugentobler Edwin , Schneider Helmut
Published: February 2015

The electrical conductivity of an argon plasma in the afterglow has been measured by means of radiowave-diagnostic. The radiation of some ArI and ArII lines as well as the electron density are determined as a function of time. The relative population of the Ar lines (Boltzmann plot) are in agreement with the temperature as taken from Spitzer’s formula using the measured conductivity within errors, except at the very early afterglow. The observed intensities of the Arl lines and the measured electron density indicate that LTE exists for the excited states. However, the groundstate appears to be strongly underpopulated.
Elektrische Leitfähigkeitsuntersuchungen an einem smektischen flüssigen Kristall mit mehreren Mesophasen
Authors: Heppke G. , Benavent W. E. Montserrat , Schneider F.
Published: February 2015

3- [N- (p-Ethoxybenzilidene) -amino] -6-n-butylpyridine (ÄBBP) exhibits one nematic and two smectic mesophases. The electric conductivity of ÄBBP is studied as a function of temperature and is found to be strongly anisotropic in the smectic phases. The value parallel to the smectic layers is up to ten times higher than in the perpendicular direction. The parallel and perpendicular conductivities give different energies of activation, which is discussed on the basis of the McMillan theory.
The Orientation Dependence of the Electron Backscattering Coefficient of Gold Single Crystal Films
Authors: Drescher H. , Krefting E. R. , Reimer L. , Seidel H.
Published: February 2015

A theory is developed for calculating the orientation dependence of the backscattering coefficient of single crystal films. Three contributions are calculated separately; firstly the direct Lackscattering out of the Bloch wave field, secondly the backscattering of electrons scattered out of the wave field into angles smaller than 90° and thirdly the remaining fraction of electrons scattered into very small angles. The electron diffusion is considered by Monte-Carlo calculations. The results are approximated by simple analytical formulas for computation. The theory is compared with experiments on gold single crystal films on a mica substrate. For primary electron energies below 6 keV, a decrease of the orientation anisotropy of backscattering is observed with decreasing energy, whereas Si and Ge single crystals show a further increase. This decrease agrees with numerical calculations using cross sections for low energies.
Mikroskopische Theorie der Kernreaktionen für einen Mehrteilchen-Aufbruch / Microscopic Theory of Nuclear Reactions for a Multi-particle-break-up
Authors: Grauel A.
Published: February 2015

Introducing correlated continuum wave functions for the two- and re-particle-continuum a microscopic theory of nuclear reactions based on a method of Fano is developed. The S-matrix-elements are given by the matrix-elements between correlated continuum wave functions and bound state wave functions. The antisymmetrization of the continuum wave functions with more than one particle in the continuum is included. The theory can be straightforwardly applied on the n-nucleon-emission process following photo- and particle excitations.
Aspects of Quantitative Determination by Ion Probe of Fluorine Concentrations in Apatites
Authors: Lodding A. , Gourgout J.-M. , Petersson L. G. , Frostell G.
Published: February 2015

In studies of F concentrations in apatite crystals by means of secondary ion micro-analysis, it is found that even in a sample with a known and constant F/Ca ratio the recorded ratios of the F and Ca secondary ion currents can vary widely, depending on the experimental conditions of primary bombardment. An attempt has been to explain this behaviour and to devise a way to obtain quantitative atomic F to Ca ratios independent on measuring conditions. Simultaneous recording of the mass peaks of F+, Ca+ and another matrix ion (P+ or C++) appears to offer a solution of the reproducibility problem. This is demonstrated by ion probe measurements under varied conditions in three groups of materials where the F concentrations had previously been determined by macroscopic methods: apatite crystals with about 3% F, whale teeth of about 10-1 % F, and human enamel ob about 10-2 % F.
Eigenvalue Equations with Dressed Propagators in a Pole Regularized Spinor Theory
Authors: Dammeier K.
Published: February 2015

The massless Green's function in a pole regularized nonlinear spinor theory is dressed and the resulting eigenvalue equations are discussed. The coupling constant is more than doubled by this dressing, and the boson solutions change drastically. The old solutions disappear, a singlett deuteron solution with small binding energy appears. The fermion propagator is determined from a selfconsistency requirement.
Interpretation of Electron Channeling by the Dynamical Theory of Electron Diffraction
Authors: Kambe K. , Lehmpfuhl G. , Fujimoto F.
Published: February 2015

The connection between electron channeling and electron diffraction is discussed on the basis of the dynamical theory. Results of the many-beam calculations for 50 keV to 2 MeV electrons incident almost parallel to a [110] axis of a MgO crystal are used as examples. Bloch waves with a marked concentration of electron density at rows of atoms are obtained, and interpreted as states of electrons bound to the rows of atoms, corresponding to the classical picture of channeling. This can be shown properly by applying the tight-binding method of band theory in the two dimensions perpendicular to the axis. In this picture the "rosette motions"' in the classical theory are interpreted as p-tvpe, d-type, etc. Bloch waves, and the "weavons" as loosely-bound s-type Bloch waves. They are connected to the pictures of the Borrmann effect and the Bloch-wave channeling in the diffraction theory.
Zu Stofftransport und Hydrodynamik der Pulsationsdiffusion
Authors: Beßerdich H. , Kahrig E. , Lange Fr.
Published: February 2015

The pulsation diffusion method is used successfully for the determination of diffusion coefficients in different systems (selfdiffusion, binary and ternary mixtures) and in connection with diffusion separation in liquids. The main advantage is the enhancement of matter transport by periodic flow e. g. in a capillary. Adapting a computation by P. L. Kapiza it is reported on a general treatment for the special conditions in a pulsation diffusion apparatus. Transport behavior depends strongly on hydrodynamic and mass transfer parameters. The results are important for the application of the pulsation method for measuring diffusion coefficients and for separation problems.
Dielectric Behaviour of the Ferroelectric AgNa(NO2)2 and Spin Lattice Relaxation of 23Na
Authors: Grossmann J. , Müller D. , Petersson J.
Published: February 2015

The characteristic ferroelectric dispersion of the dielectric constant of AgNa(NO2)2 is measured near the ferroelectric phase transition. In accordance with other works an extremely slow relaxation is observed which can be related to a thermally activated motion of the electrical dipoles. The nuclear spin lattice relaxation time T1 of 23Na in AgNa(NO2)2 is measured by 90° - t-90° pulse sequences. In the entire temperature range the temperature dependence of T1 is governed by a thermally activated process which is ascribed to a diffusional motion. There is only a small influence of the dielectric instability on T1.
How to Measure the Spinor Character of Fermions
Authors: Drope Eckard
Published: February 2015

A spinor is a geometrical object which changes its sign under a 2 π-rotation. As fermions are described by spinors the question arises if spinors are mere mathematical tools or if they have physical reality. We propose an experiment from which the spinor character of fermions can directly be read. We take this opportunity to put the Stern Gerlach experiment into the language of the quantum theoretical measuring process.
Magnetically Induced Plasma Rotation
Authors: Witalis E. A.
Published: February 2015

The extensively studied and controversial question about the origin of the observed fast rotation for magnetically confined plasmas, in particular theta pinches, is briefly reviewed. It is shown that standard MHD equations predict the experimentally observed rotation. The effect is interpreted as a form of the Einstein-de Haas effect. The generally accepted continuum plasma reasoning which denies any appreciable electromagnetic angular momentum transfer to an azimuthally symmetric plasma volume is shown to be too simplified.
Thermomagnetic Force for Small Spheroidal Particles
Authors: Vestner H. , Adair T. W.
Published: February 2015

The thermomagnetic force for small spheroidal particles is given in the Waldmann limit. In this limit the force is proportional to the surface area of the particle, and depends on the gas pressure p and on the magnetic field strength H only via H/p. For the gases HD, CH4, CO and N2 the ratio of the thermomagnetic and thermal forces is calculated from Senftleben-Beenakker effect data. It is pointed out that the sign and magnitude of the thermomagnetic force in the Waldmann limit give information on the relative sign of two non-diagonal collision cross sections. The dependence of the force on the orientations of the magnetic field and of the axis of the particle relative to the temperature gradient is discussed.
Precise Values for Critical Fields in Quantum Electrodynamics
Authors: Soff Gerhard , Müller Berndt , Rafelski Johann
Published: February 2015

A careful investigation of different corrections to binding energies of electrons in almost critical fields is performed. We investigate quantitatively the influence of the nuclear charge parameters, nuclear mass, degree of ionization on the value of the critical charge of the nucleus. Rather qualitative arguments are given to establish the contribution of the quantumelectrodynamic corrections, which are found to be small. Some phenomenological modifications of QED are quantitatively investigated and found to be of negligible influence on the value of the critical field. For heavy ion collisions with Z1+Z2>Zcr the critical separations between ions are given as results of precise solutions of the relativistic two coulomb center problem. Corrections due to electron-electron interaction are considered. We find (with present theoretical accuracy) Zcr=173±2, in the heavy ion collisions Rcr(U-U) = 34.7±2 fm and Rcr (U-Cf)=47.7±2 fm. We shortly consider the possibility of spontaneous muon production in muonic supercritical fields.
Messung der kohärenten Streuamplitude für die Neutron-Deuteron- Wechselwirkung am Neutronenschwerkraftrefraktometer des FRM / Measurement of the n-d Coherent Scattering Amplitude Using the Neutron Gravity Refractometer at the Research Reactor of the Technical University of Munich
Authors: Nistler Wolfgang
Published: February 2015

Measurements of the coherent scattering amplitudes of various mixtures of heavy and light water are reported. By means of mirror reflection technique the coherent scattering amplitudes of the D2O and H2O molecule are determined to be 19.148±0.004 F and -1.679±0.004 F, respectively. Use of aH=-3.740±0.003 F, obtained by the same technique, yields aD=6.674±0.006 F as the bound scattering amplitude of the deuterium nucleus. This value disagrees with the widely accepted 6.21±0.04 F, reported by Bartolini et al. in 1968.
Optische und elektrische Eigenschaften kristalliner Chelatodicarbonyliridium(I)-Komplexe / Optical and Electric Properties of Crystallized Chelatodicarbonyliridium(l) Complexes
Authors: Aderjan R. , Keller H. J. , Rupp H. H.
Published: February 2015

A series of complexes crystallizing in a columnar structure were prepared. They have the stoichiometry Ir(CO)2ClL and Ir(CO)2L-L, where L = monodendate neutral organic base and L-L = mononegative bidendate organic ligand. UV-VIS-spectra and conductivity measurements at variable temperatures show that with increasing size of the ligand system, the intermolecular metal interactions strongly diminish. Therefore these systems are inconvenient as possible exciton superconductors.
Zum thermodynamischen Verhalten des flüssigen Systems Wasser + Essigsäure / On the Thermodynamic Behaviour of the Liquid System Water + Acetic Acid
Authors: Haase R. , Keller M. H. , Dücker K.-H.
Published: February 2015

Vapour pressures and vapour compositions of the liquid system water+acetic acid have been measured at 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, and 75 °C in the whole range of compositions. The molar excess Gibbs function is derived from the measurements. At 50 °C, where experimental values of the molar excess enthalpy (molar heat of mixing) are available, the molar excess entropy is also given.
Untersuchungen zur Quantenkondensation
Authors: Lin P. L.
Published: February 2015

It has recently been proved that quantum condensation can possibly occur only when the thermodynamic limit is formed with respect to all three space dimensions. Following this idea, it is shown that a rotating system is practically one-dimensional and therefore does not permit quantum condensation. The same is true for a charged system in an external magnetic field. However, an exact proof is given only for a second order phase transition.
Angeregte Zustände des Fluormoleküls
Authors: Kasseckert E. , Wirsam B.
Published: February 2015

For the lower lying excited states of the fluorine molecule elaborated SCF-CI calculations have been carried out. The discussion of the potential curves of some higher excited stable states leads to the conclusion that the experimentally observed orange band-system may belong to two transitions 1Σg
+ - 1Πu and 1Σu
- - 1Πg .
Computersimulation des Durchgangs schneller schwerer Ionen durch einkristalline dünne Goldschichten
Authors: Schmidt H. , Ewald H.
Published: February 2015

A Computer program for following the trajectories of high energy ions in a fcc-lattice has been written to study the energy loss of 60 MeV 127I ions channeled between (100)- and (111)- planes of a Au-single crystal. The motion of the ions is treated classically. It is assumed that the ion has only one important interaction at a time as it moves through the lattice. The interaction potential used in the calculation is a screened Coulomb potential with a screening function derived from Thomas-Fermi-theory. The slowing down of the incident ions through inelastic encounters with the atoms of the medium is described by a stopping power function which increases exponentially with the distance from the midplane of the channel walls.
Non L.T.E. Populations and Related Quantities for H-H+-e Plasmas as a Function of the Cut-off Level
Authors: Cacciatore M. , Capitelli M.
Published: February 2015

The influence of the choice of the cut-off level n* of the evaluation of the coefficients of quasistationary plasmas has been studied. The numerical results show that the coefficient r1(i) which represents the contribution of the population density of the ith excited level by direct excitation from the ground level, is strongly affected by the choice of n*. A minor influence is observed 1) on the coefficient r0(i) which represents the contribution to the population density of the ith level from the continuum of free electrons 2) on the collisional-radiative recombination (α) and ionization (S) coefficients'.
Optische Doppelbeugung und LEED
Authors: Heinz Klaus
Published: February 2015

The phenomenon of double diffraction in the Fraunhofer case can be assumed to occur also in LEED. Double diffraction spots can cancel in special geometric arrangements.
Löschung der Perylen-Fluoreszenz durch Schweratom-induzierte intermolekulare Singlett Triplett-Energieübertragung
Authors: Zander M. , Dreeskamp H. , Koch E.
Published: February 2015

The fluorescence of perylene is quenched by bromonaphthalene but not by bromo-benzene. This is explained with the assumption of an intermolecular energy transfer from the fluorescing state S1 of perylene to the lowest triplet state T1 of the halogen-naphthalene.
Molecular Beam Measurement of the Hyperfine Structure and Zeeman Effect of 85Rb19F
Authors: Hollowell Craig D. , Lange Florentin
Published: February 2015

Hyperfine structure and Zeeman effect of the 85Rb19F molecule have been measured with a molecular beam apparatus using electric four poles as deflecting fields and homogeneous superimposed electric and magnetic fields in the transition region. Electric dipole transitions were induced between the hyperfine structure levels of the first rotational state J = 1 and the two lowest vibrational states υ = 0 and υ=1 for the strong field case. The following quantities were determined and are compared with results from weak field measurements: the magnetic rotational dipole moment µJ, the nuclear spin-rotational interactions c1, and c2 (1⍙Rb, 2⍙F) the scalar and tensor part of the nuclear dipole-dipole interaction ds and dT, the quadrupole coupling constant eqQ of the Rb nucleus, the anisotropy of the magnetic susceptibility ξ⊥ – ξ∥, the anisotropy of the magnetic shielding of the external magnetic field at the position of both nuclei (σ⊥–σ∥)1 and (σ⊥–σ∥)2, the magnetic moment of the Rb nucleus multiplied by the scalar part of the magnetic shielding tensor µ1 (1-σ)1.
Luminescence of Cr2+ Centres and Related Optical Interactions Involving Crystal Field Levels of Chromium Ions in Zinc Sulfide
Authors: Grebe G. , Schulz H.-J.
Published: February 2015

In the i.r. emission of ZnS:Cr crystals, a zero-phonon doublet at 5211 and 5216 cm-1 and a number of vibronie bands are resolved at T ≈ 4 K. The Td symmetry of the crystal field at the Cr2+ ion on a Zn lattice site is reduced to D2d by a static Jahn-Teller effect. Differences in the vibronie structures of absorption and emission indicate prevalence of quasi-local vibrations in the spectra. An exponential decay of the i.r. luminescence in the μs range yields an oscillator strength f = 6×10-4 (T = 4K) in accordance with selection rule reasoning for the radiative transition 5A1(5E)→5B2(5T2).

By interrelating a fit of transmission spectra with excitation spectra of luminescence and photoconduction, the distance of the Cr2+ centres from the conduction band edge is evaluated at 20700 cm-1 (T = 300 K). An irradiation of the crystals with photons of energies above this optical ionization threshold causes a sensitization for the Cr2+ i.r. luminescence. Thus, apart from effects related to traps, a novel excitation band at 10500 cm-1 arises which is interpreted by the 6A1(6S)→4T1(4G) transition of Cr+ centres. This transition terminates in a level degenerate with conduction band states so that free carriers will be released which, in turn, induce the Cr2+ emission.

Furthermore, at some of the crystals, the i.r. emission between 2500 and 3000 cm-1 of Fe2+ centres is recorded with the best resolution obtained so far.
Studies of Separation Distances in a Magnetically Driven Shock Tube with Parallel-Plate Electrodes
Authors: Chang C. T.
Published: February 2015

The separation distances between the pressure, the luminous, the ionization and the current front in a magnetically driven shock tube were investigated under discharge conditions of constant voltage and variable pressures. In order to achieve a steady-state, one-dimensional flow- parallelplate electrodes and a constant voltage energy source were chosen, onventional magnetic probe and piezo-electric probes were used as diagnostic tools. These were suplemented by Schlieren and holographic interferograms. Experimental results show that the observed lack of separation at low discharge pressures can be attributed to the diffusive nature of the driving current. Due to the presence of anomalous diffusion, its cause cannot be entirely explained by present theories.
Der Einfluß der Elektronenaffinität auf die optisch stimulierte Exoelektronenemission von KCl / Influence of the Electron Affinity on the Optically Stimulated Exoelectron Emission (OSEE) of KCl
Authors: Kriegseis W. , Scharmann A. , Seibert J.
Published: February 2015

The OSEE of KCl single crystals due to optical bleaching of F-centers created by electron bombardment has been investigated under various vacuum conditions. Its decay and intensity revealed a strong dependence on the residual gas pressure which can be explained by alterations of the electron affinity.
Light Optical Convolution Computers in Electron Microscopy
Authors: Hoppe W. , Guckenberger R.
Published: February 2015

Correlation functions of electron micrographs calculated by light optical computers allow to visualize astigmatism and defocusing.
Monte Carlo Computations on Molten Caesium Bromide
Authors: Margheritis Chiara , Sinistri Cesare
Published: February 2015

Molten CsBr was computer simulated tat 1 atm and four different temperatures using the Monte Carlo method. Structural and thermodynamic properties of the melt were obtained on the basis of pair potentials. In particular, radial distribution functions, volume, and energy with its coulomb, dipole-dipole, and repulsive components were determined. Separately, the polarization energy was also evaluated: this quantity increases with increasing temperature and ranges between 2 and 4% of the total energy.
Scheinbare Reflexion schneller Elektronen bei streifendem Einfall / Apparent reflection of fast electrons for glancing incidence
Authors: Mandour M. Abou , Harder D.
Published: February 2015

Backscattering of 20 MeV electrons from lead is simulated by a Monte Carlo code for varied angles of incidence. For glancing incidence, the most probable exit angle approaches the reflection angle, and the most probable energy approaches the initial energy. The underlying mechanism is derived from the calculations. Beam collimators for electron therapy may be improved by consideration of this effect.
Comparison of Faddeev Method and Resonating Group Method above Breakup Threshold
Authors: Söhre F. , Schmid E. W.
Published: February 2015

The reliability of the resonating group method is studied above the three-body breakup threshold. In particular, the real part of the elastic n-d phase shift is calculated in a model of three spinless bosons interacting by a separable Yamaguchi potential for which exact Faddeev results are available. Spurious singularities which are caused by the distortion part of the resonating group ansatz are eliminated by a least squares method.
Temperaturabhängigkeit der statischen Dielektrizitätskonstante und des optischen Brechungsindexes von Flüssigkeiten
Authors: Gryczyński I. , Kawski A.
Published: February 2015

A variation of the temperature changes the static dielectric constant (ε) and the refractive index (n) of solvents and, in conjunction with the measurement of solvent shifts of absorption and fluorescence maxima, allows the investigation of dipole moment changes of solutes in the excited state. For this purpose, investigations of the temperature dependences of ε and n of some pure and mixed solvents of different polarities have been made. It is found that the excited dipole moments of indole, 1,2-dimethylindole, 2,3-dimethylindole and tryptophan obtained from the shifts of the fluorescence maxima in mixed solvents at high temperatures are in good agreement with those obtained in other ways.
Massenspektrometrische Bestimmung von Bindungsenergien in siliciumorganischen Verbindungen / Mass-spectrometric Determination of Bond Dissoziation Energies in Organosilicon Compounds
Authors: Potzinger P. , Ritter A. , Krause J.
Published: February 2015

The appearance potentials for a large number of organosilicon ions have been measured. Combination of these values with thermochemical heats of combustion allow the determination of bond energy terms which may be used to calculate heats of formation for all silicon compounds containing hydrogen, alkyl and chlorine ligands. The bond dissoziation energies D(Si - H)= 89 ± 4, D(Si - C) = 85 ± 4 and D (Si - Si) =75 ± 8 kcal/Mol were found to be independent of the number of methylgroups attached to silicon. In addition the Si - Cl bond energy was found to be 116 and 104 kcal/Mol in (CH3)3SiCl and Cl3SiCl respectively.
Optically Detected Spin Locking of Zero Field Electronic Triplet States and Cross Relaxation in the Rotating Frame
Authors: Schuch H. , Harris C. B.
Published: February 2015

The spin locking method known from NMR is shown to be useful also in ESR for investigating spin lattice relaxation problems and “slow” motions, e. g. questions of energy transfer by triplet states in organic molecular crystals, and probing of nuclear quadrupolar splittings even smaller than the ESR line width at zero magnetic field.

Optically detected ESR spin locking experiments for isolated triplet states in zero field are demonstrated. It is shown how the complication of incoming and decaying triplet states and relaxation between all three triplet sublevels has to be handled during spin locking. An application, the study of the cross-relaxation between electronic triplet spin states and deuteron or proton spins is presented. These experiments are possible in spite of the first order quenching of the hyperfine coupling in zero magnetic field. Another application is briefly mentioned, in which the adiabatically demagnetized state in the rotating frame is used to probe the electronic triplet state transfer and nuclear spin lattice relaxation.
Quantitative Investigation of the Radiation of the Negative Iodine Ion
Authors: Neiger Manfred
Published: February 2015

A pure iodine plasma is generated by a cylindric arc at 1 atm and 6 to 30 amps within a quartz tube of 8 mm diameter. The radiation emitted along the arc axis was measured absolutely in the wavelength range from 0.2 -1.9 μ. In the uv-region it consists mainly of the affinity continuum due to transitions of free electrons to the ground level of the negative iodine ions. The first threshold of this continuum at 4048 Å yields an electron affinity of the iodine atom of 3.062 eV. The resulting photodetachment cross-section of the I--ion exhibits a broad peak at 2400 Å, which can be attributed to a I--compound-state. The continuous background radiation in the visible and infrared regions shows, after subtraction of the electron-ion continuum, two long-wavelength thresholds near 1.25 μ and 0.64 μ. The absolute intensity of this radiation, its wavelength and temperature dependence and its threshold energy and threshold structure suggest the contribution of two dominant radiation processes: a second affinity continuum due to an excited state of the I--ion about 2 eV above the ground level and an association continuum of I2
+-molecules. Towards longer wavelengths λ>1.5 μ electron-atom Bremsstrahlung becomes more important.
Effective Interionic Potentials and Properties of Molten Noble and Transition Metals
Authors: Waseda Y. , Ohtani M.
Published: February 2015

Recent X-ray diffraction data on molten noble and transition metals have been used to calculate effective interionic potentials by means of the Born-Green equation. The results on the noble metals are compared with the generalized pseudopotential calculations of Moriarty. In all cases the potentions were found to be insensitive to temperature and to have long-range oscillations. The results suggest that the effective valence number is close to unity in these molten metals, this giving reasonable values of the electrical resistivity when calculated in the framework of the usual Ziman theory.

The self-diffusion coefficients, viscosities and surface tensions were calculated from the poten-tials and radial distribution functions using the kinetic theory of fluids. Adequate agreement with experimental data was obtained.
Strukturbestimmung von Chlorfluorthiocarbonyl durch Elektronenbeugung / The Structure of Thiocarbonyl-chloro-fluoride as determined by Gas-Electron-Diffraction
Authors: Gleisberg F. , Haberl A. , Zeil W.
Published: February 2015

Gas electron diffraction (GED) intensities of CSFCl were measured and resulted in an ra- structure of this molecule. An rav-structure was obtained by combining our GED-data and the rotational constants reported by Kohrmann and Zeil. Both structures were found to be consistent within their uncertainties. The planar structure of CSFCl has been confirmed. A least squares analysis resulted in the following rg-distances and bond angles: r(C-Cl) =1.7178±0.0009 Å, r(C=S) =1.5931 ±0.0008 Å, r(C-F) =1.3387±0.0014 Å, ∢ S = (C-Cl)=127.28 ± 0.09°, ∢(S=C-F)= 123.58 ±0.12°.

Inclusion of rotational constants into the GED-analysis allowed an experimental determination of all mean square amplitudes (MSA). We have used the valence force constants obtained by Kohrmann to evaluate the MSA theoretically. Qualitative agreement was found between the theoretical and experimental values of the MSA.
Fourier-Kernresonanzuntersuchungen an 10 B und 11 B in wäßriger Lösung / Fourier Transform NMR Studies of 10 B and 11 B in Aqueous Solutions
Authors: Epperlein B. W. , Lutz  , Schwenk A.
Published: February 2015

The ratios of the Larmor frequencies of 10 B and 2 H and of 11 B and 10 B have been measured with the NMR method and a magnetic moment has been calculated for 10 B in the B (OH)4
- -ion. For this, an investigation of the dependence of the NMR signals of 10 B and 2 H on the concentration of some boron salts in solutions of H2O and D2O was necessary. Using hyperfine interaction constants from literature, the hyperfine structure anomaly 10 ∆ 11 of boron in the 2 P1/2 atomic ground state has been calculated. A difference in the magnetic shielding between the isotopes 10 B and 11 B in different compounds could not be detected.
Form Factors for Rotational Levels in 12C, 16O, 28Si and 40 Ca
Authors: Lezuo K. J.
Published: February 2015

We support the proposed ground state rotational bands in 12 C, 16 O, 28 Si and 40 Ca by calculating the form factors for the electro-excitation within a simple model. The model introduces two parameters for the size and the surface thickness of these nuclei and allows for the prediction of the transition probabilities and form factors within the rotator model. The model unambiguously predicts the sequence of rotational levels 0+, 3+ , 4+ ... for 16 O and 40 Ca, and 0 + , 2 + , 4 + ... for 12 C and 28 Si in agreement with the experiment. The comparison of the calculated form factors with the experimental data shows excellent agreement in the cases 28 Si and 40 Ca and is less satisfactory in the cases 12 C and 16 O.
Notizen: E-Typ-verzögerte Fluoreszenz von 1,1′-Dicoronyl in einer Kunststoffmatrix / E-type Delayed Fluorescence of 1,1′-dycoronyl in a Plastic Matrix
Authors: Zander M.
Published: February 2015

E-type delayed fluorescence of 1,1′-dicoronyl (III) has been established by measurement of luminescence lifetimes and activation energy.
Fourier Transform Nuclear Magnetic Resonance Studies of 25Mg and 43Ca
Authors: Lutz O. , Schwenk A. , Uhl A.
Published: February 2015

The ratios of the Larmor frequencies of 25Mg and 37Cl and of 43Ca and 37Cl have been measured in aqueous solutions and nuclear magnetic moments are given for these nuclei in the hydrated ions.

25Mg and 43Ca chemical shifts have been investigated at natural abundance of these isotopes in solutions of the chlorides, bromides, nitrates, Perchlorates in H2O and D2O. The signal intensities are large enough to study within reasonable time these nuclei at natural abundance down to low concentrated solutions, e.g. 8 millimolal for 25Mg. For 25Mg very small chemical shifts have been observed whereas for 43Ca remarkable shifts to higher frequencies are found for halide solutions and to lower frequencies for the oxyanion solutions. Linewidths of only some Hz have been observed for both isotopes
Van der Waals Forces between Copper and Noble-Gas Atoms
Authors: Bielski A. , Szudy J.
Published: February 2015

The Van der Waals constants for the five lowest energy levels of Cul interacting with noble-gas atoms have been calculated using a semiempirical method. A comparison with the values obtained from the Coulomb approximation is presented
Direct Correlation between Diffusion Coefficient and Transport Numbers in Dilute Electrolyte Solutions
Authors: Haase R.
Published: February 2015

For dilute solutions of a strong electrolyte containing two kinds of ions, there is a direct correlation between the diffusion coefficient and the transport numbers. This follows from the Onsager and Onsager-Fuoss equations by elimination of the electrophoretic term
Some Remarks on the Evaluation of Concentration Spectra in Solids From X-Ray Diffraction Profiles
Authors: Schattschneider P. , Wagendristel A.
Published: February 2015

The validity of some assumptions included in the theoretical basis of several x-ray methods for the determination of concentration spectra in inhomogeneous solids, is analysed critically by theoretical considerations.
Observation of Turbulent Waves in a Helium Plasma by Optical Spectroscopy
Authors: Rutgers W. R.
Published: February 2015

From the combined Stark-Zeeman pattern of helium allowed and forbidden optical lines the frequency spectrum, the field strength and the dominant polarization of microfields were determined in a turbulent plasma. Two frequency domains of oscillations were found in a turbulent heating experiment: low-frequency oscillations with dominant polarization perpendicular to the current direction and high-frequency oscillations (f~fpe) with random polarization. The r.m.s. field strength of the oscillations is between 2 kV/cm and 10 kV/cm. The energy density of turbulent microfields amounts to 1‰ of the thermal energy density.
Verbesserung des Meß-und Auswerteverfahrens zur Bestimmung der gemeinsamen und partiellen Diffusionskoeffizienten am Beispiel von Kupfer-Gold-Legierungen/An Improved Method for Measuring and Analysing Chemical and Intrinsic Diffusion Coefficients Applied to Copper-Gold Alloys
Authors: Heumann Th. , Rottwinkel Th.
Published: February 2015

A method is described which enables the determination of the chemical diffusion coefficients D̃ in a binary system as well as the intrinsic diffusion coefficients of both components with sufficient accuracy. The difference in concentration between the diffusion couples should not exceed 5 at%. Numerous diffusion profiles at different annealing times are taken by electron microprobe analysis from each specimen before calculating D̃ according to a method proposed by Sauer and Freise Combining the results for different pairs of specimens with overlapping concentration range mean values of D̃ are obtained in the total concentration range unter consideration. An analytical expression for D̃ is given, which is used to determine the diffusion profile for a special diffusion couple according to the method of Wagner4 . By this one obtains the total diffusion profile including the flat ends which cannot be accurately determinated by electron microprobe analysis. The determination of the intrinsic diffusion coefficients according to van Loo5 is based on these calculated profiles with additional knowledge of the position of the welding interface. This method has been applied to diffusion measurements in Cu-Au alloys. The following relation for D̃ has been found in the concentration range between 0 and 32 at% Au at 911 °C

D̃(N)Cu Au
911 °C =3,71·10-10 + 5.04·10-9 N+1.76·10-10 N2 + 1.01 -10-11 N3 [cm2 sec-1 ]. N = mole fraction of Au.
Erzeugung von freien Defektelektronen in 2,3 Dimethylnaphthalin- Einkristallen mit schwach absorbiertem Licht/ Photo generation of Holes in 2,3-Dimethylnaphthalene by Weakly Absorbed Light
Authors: Falter W.-W.
Published: February 2015

Irradiation of 2,3 DN single crystals by 5 nsec light pulses from a nitrogen laser (337 nm) and by 20 nsec light pulses from a Q-switched ruby laser (347 nm, second harmonic) respectively, causes generation of free holes. Centers which are most probably associated with crystal defects are electronically excited by the incident light directly or by energy transfer from the primary excited 2,3 DN. The excited centers are quenched by charge transfer interaction with 2,3 DN. Mobile holes are separated from the localized negatively charged centers subject to the applied electric field. The centers are distributed uniformly over most of the volume, but in a region closer than 1 μm to the surface the concentration increases rapidly. In this surface layer also a high density of hole traps are found to exist, which are responsible for the temperature dependent rise of the photocurrent pulses below room temperature. At high current densities recombination between ionized centers and drifting holes becomes important. The recombination coefficient is found to be 10-5 cm3 /sec. Analysation of the fast (60 nsec) rise of the photocurrent pulses above room temperature gives information about the lifetime of the excited centers and about the lifetime of the singlet excitons in the surface layer. Values of ≈ 30 nsec for the centers and ≲ 10 nsec for the excitons are found. The volume lifetime of the singlet excitons is measured to be 80 nsec.
Notizen:Values for the Electron Screening in Muonic Atoms for all Z
Authors: Fricke B. , Telegdi V. L.
Published: February 2015

The electron screening correction in the X-ray transitions in muonic atoms is calculated within a relativistic SCF Hartree-Fock procedure for many transitions and all Z.
Energieübertragung in Anthracen dotierten 2,3 Dimethyl- naphthalin-Einkristallen im Temperaturbereich 4K < T < 300 K / Energy Transfer in Anthracene Doped 2,3 Dimethylnaphthalene Single Crystals
Authors: Ganz P.
Published: February 2015

The fluorescence spectra and the decay time of emission bands of pure and anthracene doped 2,3 Dimethylnaphthalin single crystals excited by short light pulses were examined for temperatures of 4 to 300 K.

On raising the temperature from 40 to 120 K the decay time and the relative quantum yield of 2,3 DN decreases, the emission is shifted by about 150 cm-1 to higher energies and simultanously the energy transfer to the anthracene impurity molecule increases.

A model calculation is presented which allows a theoretical interpretation of the experimental results
Mößbauer-spektroskopische Untersuchungen am System Fe1+xSb mit NiAs-Struktur/ Mössbauer-spectroscopy in the system Fe1+xSb with NiAs-structure
Authors: Richter F. W. , Schmidt K.
Published: February 2015

Measurements in the system Fe1+xSb for 0.13 ≦ x ≦ 0.30 and in the temperature range 10 K ≦ T ≦ 625 K are represented.

In the paramagnetic phase one observes a small quadrupole splitting of ΔνQ=0.272 (8) mm/s, independent of the non-stoechiometric portion x. From the temperature dependence of the isomeric shift δ a Debye-temperature θ= (766 ± 100) K was determined.

Néel temperatures are found to be about 211 K, varying smoothly with x, according to an increased number of bipyramidal FeII-atoms and therefore a stronger influence of the ferromagnetic coupling with octaedral FeI-atoms.

The measured Mössbauer spectra in the antiferromagnetically ordered phase can only be interpreted as a superposition of several magnetic line-sextets, probably due to a variation of the local magnetic field at the site of 57Fe, with different numbers of nearest Fe-atoms. An exact assignment of the analysed fields to the number of nearest Fe-atoms was not possible.

The magnetic saturation fields are in between 95 kG and 155 kG increasing with x. The direction of the local fields are found to be parallel to the plane (001) of the NiAs-lattice.
Ein Verfahren zur Untersuchung von Phasenumwandlungen flüssiger Kristalle durch elektrische Leitfähigkeitsmessungen/ Investigation of Phase Transitions in Liquid Crystals by Means of Electrical Conductivity Measurements
Authors: Heppke G. , Schneider F.
Published: February 2015

A procedure for determining the transition temperatures of liquid crystals is described which is based on observation of the electrical conductivity as a function of temperature. It is found in particular that plotting the function d lg x/dT against the temperature gives a resolution and a sensitivity comparable to that of thermal methods of analysis (DTA and DSC). Dynamic orientation effects of the liquid crystals in the sample cell which usually lead to an increase in sensitivity are discussed. The phase diagram of the system 4,4ʹ-di-n-pentyloxy-azoxybenzene/4,4ʹ-di-n-heptyloxy-azoxybenzene determined using the electrical conductivity method is presented.
Graph Theory in Chemistry II. Graph-Theoretical Description of Heteroconjugated Molecules
Authors: Graovac A. , Polansky O. E. , Trinajstić N. , Tyutyulkov N.
Published: February 2015

The Sachs' formula which relates the structure of a (vertex-and edge) -weighted graph and its characteristic polynomial is given. Weighted graphs are used to represent conjugated molecules containing the variety of heteroatoms and heterobonds. Vertices and edges in such molecular graphs have different weights following the deviation of the corresponding (Hiickel) Coulomb and resonance integrals from the standard (benzene) values.