bluuebunny/crossref_metadata_2025 huggingface dataset:
Die Thermokraft von kubisch stabilisiertem Zirkonoxid zwischen Sauerstoffelektroden
Authors: Fischer W.
Published: March 2015

The thermoelectric power Δφ/ΔT [mV/grad] of cells of the type O2 | T stabilized zirconia | T + ΔT O2 has been determined as a function of oxygen partial pressure p [Torr] in the temperature range 960°K ≦ T ≦ 1310°K. The experimental results can be described by the equations

-Δφ/ΔT=0,492+0,0220 ln(159/p) for (ZrO2)0,88(CaO)0,12 and

-Δφ/ΔT=0,460+0,0219 ln (159/p) for (ZrO2)0,91(Y2O3)0,09.

The change of Δφ/ΔT with oxygen partial pressure corresponds to the change of partial molar entropy of O2.

The heats of transfer of oxygen ions are estimated from experimental results and thermodynamic data. From the negative sign of the heat of transfer it is concluded, that oxygen ions migrate by a vacancy mechanism, which has been established also by experiments of other authors.
On a Gyro-Thermal Effect with Polyatomic Gases in a Magnetic Field
Authors: Waldmann L.
Published: March 2015

SCOTT, STURNER and WILLIAMSON observed that a polyatomic gas exerts a torque on a heated cylinder if a homogeneous magnetic field parallel to the axis is present. This effect is explained, for high enough pressure, by the kinetic theory of polyatomic gases. Decisive is the huge “amplification of spin” occurring when spin is transferred from molecules to cylinder in “cut tennis ball reflexion”. Phenomenologically this is manifested in the boundary condition (4): the gas shall have a slip velocity, tangential to the wall, which is proportional to the tangential component of its “azimuthal polarization”.
Isotopenanalyse der Edelgase in einem Tellurerz von Boliden (Schweden)
Authors: Kirsten T. , Gentner W. , Müller O.
Published: March 2015

The stable He-, Ne-, Ar-, Kr- and Xe-isotopes and the Te-, K-, U-, Th- and Se-concentrations in a Precambrian bismuth-tellurium ore have been measured. We have found an age of 0.53 x 109 y with K-Ar, 0.55 x 109 y with U/Th-He4 and 1.56 x 109 y by the U-Xe136 method.

The Xe131-excess and part of the Xe129-excess result from n-capture and subsequent decay of Te128and Te130. The remaining part of the Xe129-excess and the high U-Xe136 age give evidence for a higher neutron flux before the last cooling of the ore. The tellurium was probably associated with much more uranium than now. Before 0.54 x 109 y, differentiation of this uranium occured. Moreover, He and Ar but not all of the Xe were removed at this time. After cooling, the Xe129excess was formed by the decay of the long-lived I129 which had been formed from (n,γ) reactions on Te128 by the higher neutron flux.

From the excess in Xe130, a half life for the double β-decay of Te130 of 6.2 x 1020 y is calculated.

Besides fission-Kr, there is an excess of Kr with atmospheric composition and in addition an excess of Kr82 and Kr83 also. From the Kr82-excess and the selenium content a lower limit for the Se82-double β-decay half life of T1/2≥ 1018 y is calculated. No evidence is given for Ar38 from U-fission.
A Study of the Registration of Arsenic and Iodine Ions in Olivine and Hypersthene Crystals
Authors: Horn P. , Maurette M. , Von Oertzen W.
Published: March 2015

The registration of the trajectories of arsenic and iodine ions in olivine and hypersthene crystals, considered as “track chambers”, is reported; these trajectories are revealed by chemical etching and observed as tracks in an optical microscope.

A brief discussion concerning the different criteria which have been proposed to explain the registration of heavy ion trajectories in solids is given. It is shown that the criterion which is presently accepted is limited in its application because of the uncertainty of two basic parameters in the equation which is used.
Multicomponent Beam-Plasma Waves
Authors: Verheest Frank G.
Published: March 2015

The linearization procedure is applied to the equations governing a beam-plasma system, in which the stream velocities and the wavevector are parallel to the external magnetic induction. No special constraints are imposed on the parameters characterizing the constituent fluids in the equilibrium state of this macroscopic picture. From the MAXWELL equations an expression for the electromagnetic field of the wave is obtained and substituted in the equations of motion. The components of the first-order pressure tensors are computed in the low-temperature approximation, but without recurring to the strong magnetic induction CGL hypothesis. Since the equations of motion are now expressed only in the components of the perturbations of the drift velocities, the dispersion relations follow immediately. These relations are applicable to all beam-plasma systems comprised between the now conventional multicomponent plasma and the system of beams of charged particles. Some known cold beam-plasma cases are included in the general dispersion equations.
Über die Zündwahrscheinlichkeit einer Niederdruckfunkenstrecke bei Spannungswiederkehr nach Strombelastung
Authors: Frie W. , Michel A.
Published: March 2015

Kehrt bei einer fremdauslösbaren Niederdruckfunkenstrecke nach vorangegangener Impulsstrombelastung die Elektrodenspannung zeitverzögert wieder, so nimmt die Wahrscheinlichkeit der Selbstzündung mit fortschreitender Entionisierung ab. Die Durchbruchshäufigkeit als Funktion der Verzögerungszeit beschreibt die Wiederkehr der Spannungsfestigkeit. Eine von der Entionisierung durch ambipolare Diffusion und Volumenrekombination ausgehende Theorie der Wiederzündwahrscheinlichkeit ist in guter Übereinstimmung mit dem Experiment. Sie gilt auch für die den gleichen Mechanismen unterliegenden Ignitrons und Vakuum-Leistungsschalter.
Tracer Studies of Atmospheric Exchange Based on Measurements of Cosmic Ray Produced Sodium-22
Authors: Roedel W.
Published: March 2015

Die Ergebnisse der in Heidelberg während des Jahres 1966 durchgeführten Messungen des durch die kosmische Strahlung in der Atmosphäre erzeugten Na22 werden dargestellt. Anhand eines einfachen Modells wird versucht, von den ausschließlich am Boden gewonnenen Meßwerten auf den Austausch zwischen Stratosphäre und Troposphäre zu schließen. Die Modell-Rechnung liefert für das an Aerosole angelagerte Na22 eine mittlere Aufenthaltsdauer in der Stratosphäre von 12,3 Monaten; die durch die Tropopause ausgetauschten Luftmengen liegen nach dieser Rechnung zwischen Null (im Spätjahr) und 48 g/cm2 · Monat (im Frühjahr).

Im Anhang wird die Abnahme des durch die Kernwaffentests von 1961 und 1962 künstlich produzierten Na22 diskutiert. Es wird gezeigt, daß die künstliche Aktivität in der Atmosphäre bis auf einen vernachlässigbaren Rest abgefallen ist.
Elektronenbeugungsmessungen zur Struktur des gasförmigen Disulfans
Authors: Winnewisser Manfred , Haase Joachim
Published: March 2015

An electron diffraction investigation of unstable gaseous disulfane using the sector-microphotometer method has been carried out. The results of these measurements and the available microwave data together yield the following molecular parameters for H2S2:

d (S—H) = 1.352 ± 0.015 A, angle (HSS) = 91°57′, d(S—S) = 2.055 ± 0.001 A, dihedral angle = 90°37′ ± 3′.
Mikrowellenspektrum und Struktur von Tribromsilan
Authors: Mitzlaff M. , Holm R. , Hartmann H.
Published: March 2015

The microwave spectra of SiHBr3 and SiDBr3 have been investigated in the region from 28 to 40 GHz. From the rotational constants the following structural parameters were derived by a least square method:

dSi-H = (1,494 ± 0,009) A, dSi-Br = (2,170 ± 0,001) Å, ∢Br-Si-Br = (111,36 ± 0,25)0. The results are compared with those obtained for other Si-halogen-compounds.
Berechnung der Knight-Shift in elektronenleitenden III — V-Halbleitern
Authors: Unger Konrad
Published: March 2015

The Knight shift for III—V semiconductors with strongly negative values of the g-factor (InSb, InAs) in dependence on the concentration of free electrons is calculated. According to the band structure model of Kane we take into account the k-dependence of the effective mass, of the g-factor and of the S-like part of the conduction band wave function. The influence of the fluctuating potential caused by high doping levels, on the Knight shift and on the resonance line width is discussed.

The nuclei “feel” via contact interaction mainly the spin moments and not the orbital moments of the electrons, therefore we have a diamagnetic resonance shift in InSb, InAs. This shift increases to ΔH/H = 1 ... 2 x 10-4 (for electron concentrations n = 1,3 x 101018 cm-3) showing there a maximum, and decreases for higher electron concentrations. The existing preliminary measurements of the Knight shift show values in fair agreement with the calculated ones.
Kernrelaxation und behinderte Rotation in organischen Festkörpern bei tiefen Temperaturen
Authors: Haupt J. , Müller-Warmuth W.
Published: March 2015

The proton magnetic resonance and relaxation of o-, m- and p-xylene has been studied at various temperatures between the melting point and 2°K. Motionally narrowed second moments of the proton lines of about 10 G2 have been observed over the whole temperature range. Spinlattice relaxation is effective at rather low temperatures and can no longer be interpreted in terms of classical hindered rotations of the methyl groups. Quantum mechanical tunneling through the barriers hindering the reorientations is considered instead. Furthermore it is proposed to explain the observed decay of relaxation rates at low temperatures as a consequence of some kind of bottleneck in the energy transfer between torsional motions and other degrees of freedom in the solid. On the basis of a simplified model a quantitative explanation of the experimental data has been possible using elements of the theoretical treatment of Stejskal and Gutowsky. The potential barriers are of sixfold and of threefold symmetry. From the experimental data absolute barrier heights of 2,2 (o-xylene), 0,27 (m-xylene) and 1,1 kcal/Mole (p-xylene) could be calculated.
Stationäre und nichtstationäre Konzentrationsverteilung von Isotopen im Trennrohr
Authors: Meinrenken J.
Published: March 2015

Der Anwendungsbereich des „Theorems der unabhängigen Trennung“, mit dessen Hilfe die räumlich-stationäre Konzentrationsverteilung polynärer Isotopen-Gemische im Trennrohr ohne Entnahme berechnet werden kann, wird in Verbindung mit der Wahl geeigneter Beziehungen zwischen den Trennfaktoren verschiedener Isotopenpaare auf die Berechnung zeitlich-nichtstationärer Zustände an den Trennrohrenden ausgedehnt. Zeigt in einseitig offenen Trennrohren ohne Entnahme die Verteilungskurve des Mittelisotops ternärer Gemische im stationären Gleichgewicht ein Maximum, so wird dieses Maximum in ähnlicher Größe auch während der zeitlichen Einstellung am geschlossenen Ende durchlaufen. Das Mittelisotop wird somit unter geeigneten Bedingungen in wesentlich kürzerer Zeit angereichert. Unter gewissen Voraussetzungen kann das Mittelisotop in nichtstationären Zuständen sogar höher angereichert werden als im Gleichgewicht.
Massenspektrometrische Untersuchungen an Kondensationsprodukten von Aceton
Authors: Knof Hans , Maiwald Bernd
Published: March 2015

Mass spectra of positive and negative ions from acetone fragments are well known. This paper is concerned with heavy ions beyond the acetone mass (58). Positive ions generated by electron impact at 130 eV can be divided into groups which correspond each other through a multiple of mass 14. For negative ions the lightest mass of each group can be indentified as a complex of carbon atoms as is known by measurements with high frequency spares between graphite electrodes. The nature of these heavy ions is shown to be complexes of molecules bounded by intermolecular forces. This could be verified by measurements of the pressure dependence of the ion current.
Dispersionskurven für Anthracen, Tetracen, para-Terphenyl, trans-Stilben und Plastikszintillator NE 102 A
Authors: Amberger R. W. , Flammersfeld A.
Published: March 2015

A new method of determining the thickness of transparent platelets (5 —100 μ) was combined with OBREIMOW’S interferometric method of measuring refractive indices. The dispersion of the refractive indices of anthracene, tetracene, p-terphenyl, trans-stilbene, and plastic scintillator was determined in the visible and near ultraviolet spectral range.
Phosphoreszenz und Verzögerte Fluoreszenz von Naphthalin in verschiedenen Mischkristallen
Authors: Port H. , Wolf H. C.
Published: March 2015

Measurements of the phosphorescence and delayed fluorescence emission at temperatures between 1.6 and 50 °K are reported for the following mixed crystal systems: Naphthalene-h8 in Naphthalene-d8 and Durene; Thionaphthene, Durene and β-Methyl-Naphthalene in Naphthalene-h8 . The emitting species is either the guest molecule (trap emission) or the vicinity of the guest molecule (disturbed exciton emission of the host) . By an analysis of the temperature dependence of the intensities of delayed fluorescence and phosphorescence it can be shown that the delayed fluorescence is at least mostly due to a thermally activated triplet triplet annihilation. Triplet energy is transferred from a trap to the annihilation partner by using the exciton band of the host. Spectroscopic and thermal energy gaps between trap levels and the host exciton band are measured. In addition we report some lifetime measurements in these crystals.
Protonenspinrelaxation von Benzol an Silikageloberflächen
Authors: Michel D.
Published: March 2015

Using spin-echo-techniques the temperature dependence of the proton magnetic relaxation times T1 and T2 of adsorbed benzene has been measured in the interval between +70 °C and —140 °C. Normal benzene C6H6 and mixtures of benzene and C6D6
e were adsorbed on two sorts of silicagels which have been described elsewhere 4,9.

The effective nuclear magnetic relaxation rates of adsorbed benzene are given by four contributions: the intramolecular proton-proton interaction, the interaction between benzene protons and paramagnetic impurities of the adsorbents, the interaction between benzene protons and hydroxyl protons on the silicagel surface, and the intermolecular interaction between benzene protons. These proton relaxation mechanisms depend differently on the H/D-ratio in C6H6—C6D6 mixtures (see section 4.1).

The temperature dependence of the contributions 1/T1 intra and 1/T2 intra due to intramolecular proton-proton interaction suggests an anisotropic rotation of benzene molecules on the gel used. Furthermore, the existence of three different regions for the adsorbed benzene molecules has been inferred (see sections 4.2 and 5).
Inner Ionization Potentials of Aromatic Compounds
Authors: Eland J. H. D. , Danby C. J.
Published: March 2015

Photoelectron spectra of indene, naphthalene, azulene, biphenyl, quinoline and isoquinoline are reported, and some inner ionization potentials of naphthalene, azulene, biphenyl and biphenylene measured by an electron impact method are also given. A close correlation is found between the inner ionization potentials of the hydrocarbons and π-electron orbital energies given by the zerooverlap Hückel approximation.
Geschwindigkeitsabhängige Zwei-Teilchen-Potentiale im Ein-Teilchen-Ein-Loch-Modell der Kerne 16O und 12C
Authors: Harms Ulrich
Published: March 2015

The odd-parity states of 16Ο are calculated in the 1-particle 1-hole model using the velocity dependent forces of HERNDON et al. and GREEN. In addition some states of 12C are calculated. It is found that the potential of HERNDON et al. gives a satisfactory agreement with experiment, comparable with that of the KALLIO-KOLLTVEIT force.
Self-Diffusion in Molten Zinc Chloride
Authors: Sjöblom C.-A. , Behn A.
Published: March 2015

The self-diffusion coefficients of both ions in molten zinc chloride have been measured with the porous-frit technique 1-3. The result can be described with Arrhenius equations:

where D is expressed in cm2 s-1, R in cal mole-1 degree-1, and T in degrees Kelvin. A comparison is made with earlier data by BOCKRIS et al. 4 and an attempt is made to correlate the experimentally observed external transport number 5 and the corresponding calculated quantity 6,7.
Elektronenoptische Untersuchungen an Tellur
Authors: Klein P. , Kleinhenz K.
Published: March 2015

Starting from bulk single crystals, tellurium has been prepared for transmission electron microscopy. The foil orientation was {101̅0} , two planes of the reciprocal lattice being projected into the electron diffraction image plane. Dislocations and small angle grain boundaries were observed and could be explained by considering glide on {101̅0} and (0001). Hints for a “rhombohedral” view of the tellurium lattice were found.
Brownian Motion of Rotating Particles
Authors: Hess Siegfried
Published: March 2015

A kinetic theory for the Brownian motion of spherical rotating particles is given starting from a generalized Fokker-Planck equation. The generalized Fokker-Planck collision operator is a sum of two ordinary Fokker-Planck differential operators in velocity and angular velocity space respectively plus a third term which provides a coupling of translational and rotational motions. This term stems from a transverse force proportional to the cross product of velocity and angular velocity of a Brownian particle. Collision brackets pertaining to the generalized Fokker-Planck operator are defined and their general properties are discussed. Application of WALDMANN'S moment method to the Fokker-Planck equation yields a set of coupled linear differential equations (transport-relaxation equations) for certain local mean values. The constitutive laws for diffusion, heat conduction by Brownian particles and spin diffusion are deduced from the transport-relaxation equations. The transport-relaxations coefficients appearing in them are given in terms of the two friction coefficients for the damping of translational and rotational motions and a third coefficient which is a measure of the transverse force. By the coupling of translational and rotational motions a diffusion flow gives rise to a correlation of linear and angular velocities.
Kinetic Equations
Authors: Bahr U. , Quaas P. , Voss K.
Published: March 2015

Ausgehend von einer allgemeinen Bewegungsgleichung für die Einteilchenverteilungsfunktion aus der vorangegangenen Arbeit werden durch Partialsummation und den Grenzübergang τ → ∞ kinetische Gleichungen für verdünnte Gase und für Plasmen in Debye-Hückel-Näherung abgeleitet.
Oscillographic Polarography in Molten Nitrates
Authors: Francini M. , Martini S.
Published: March 2015

The polarographic investigation of Pb++, Cd++, Τl+, Zn++ and Ni++ ions in a KNO3-LiNO3-NaNO3 molten eutectic mixture was carried out by conventional and oscillographic (single-sweep) polarography. Experiments were carried out in the temperature range 150 —200 °C, with a dropping mercury electrode as the cathode and a Ag/AgCl electrode as anode and reference. For ions with reversible behaviour (Cd+, Pb++, Tl+) the polarographic diffusion coefficients calculated from conventional polarography data by means of the Ilkovič equation agree, within experimental errors, with those obtained from oscillographic data by the Randles-Sevčik equation at low potential change rates. At higher potential change rates deviations of the experimental peak currents from their theoretical values were observed. This is associated with a marked distortion of the wave and indicates a certain degree of kinetic control. The temperature dependence of the diffusion coefficients in the investigated range is the same for the ions with reversible behaviour and the corresponding activation energy is E= — 8.4 kcal/mole.
New Measurements of the Infrared Spectrum of H2S2 and D2S2 and Evaluation of the Molecular Force Field
Authors: Winnewisser Brenda P. , Winnewisser Manfred
Published: March 2015

The infrared spectrum of H2S2 has been reviewed in the range 4000 to 250 cm-1 and the spectrum of D2S2 has been measured for the first time. No change in the basic assignment of the fundamental bands of H2S2 has been made, although the stretching fundamentals and the combination bands can be more precisely assigned on the basis of the new information.

With the six fundamental frequencies of H2S2 and the two asymmetric fundamental frequencies of D2S2 , calculations were made to determine as fully as possible the general valence force field. It was found that only the diagonal force constants could be determined on the basis of the available data:

FSH = 4.08 - 4.09 md/Å, Fa = 0.83 - 0.85 md A/rad2,

FSS = 2.52 -2.62 md/Å, Ft = 0.0926 md Å/rad2.
Zur Desaktivierung der angeregten Zustände bei den Phenanthrolinen
Authors: Perkampus H.-H. , Knop A.
Published: March 2015

Aus dem genau zu bestimmenden Verhältnis der Quantenausbeuten der Phosphoreszenz und Fluoreszenz und den Phosphoreszenzabklingzeiten wird die Größenordnung der Geschwindigkeitskonstanten für die strahlungslosen Interkombinationsübergänge S1 → T1 und T1 → S0 abgeschätzt. Unter Verwendung der bekannten Quantenausbeuten des Phenanthrens werden ferner die Quantenausbeuten der Phosphoreszenz und Fluoreszenz für die Phenanthroline abgeschätzt.
Experimentelle Untersuchungen an einem Wasserstoff-Lichtbogen im achsenparallelen Magnetfeld. I.
Authors: Mahn C. , Ringler H. , Zankl G.
Published: March 2015

In a stationary high density d. c. arc, the electric power input is balanced essentially by heat conduction losses in radial direction. These losses increase greatly with temperature and thus they limit the axial temperatures attainable with reasonable power input.

An experiment is described in which considerably higher plasma temperatures have been obtained by reducing the coefficient of heat conduction with a superimposed axial magnetic field. At arc currents of about 2 kA and a magnetic field of 10 kG temperatures in the middle of the arc of the order of 10 eV were reached.

The measured temperature, pressure and power input of the hydrogen plasma are compared with calculated values. In particular, the coefficient of heat conduction perpendicular to a magnetic field has been determined by measuring the radial temperature profile and the electric field strength. The results agree with theoretical predictions.
Influence of a Magnetic Field on the Spin-Diffusion in a Gas
Authors: Hess S.
Published: March 2015

On the basis of the Waldmann equation for neutral particles with spin, the influence of a homogeneous magnetic field on spin-diffusion in a gas has been studied. The spin-diffusion constant for the components of the magnetic moment perpendicular to the external field is decreased. Furthermore a transverse spin-flux is found which leads to a shift of the resonance frequency if the magnetization is spatially inhomogeneous. Both effects vanish at high densities.
BERICHT: Self-Diffusion in Molten Salts. A Comparison Between Diffusion Theories and Experimental Data
Authors: Sjöblom C.-A.
Published: March 2015

A comparison between the available self-diffusion data on pure molten salts and the predictions by different liquid diffusion theories is made. It is found that the Arrhenius equation D=D0exp (— Q/R T) describes the experimental data equally well (or better) than any of the other theoretically predicted equations. The hole model prediction (Q=3.74 R Tm) is found to be inaccurate. The free volume model and the local density fluctuation models describe the data less well than the other models considered. The cubic cell model leads to a correct correlation between self-diffusion and kinematic viscosity for several salts (but not all).
Farbzentrenbildung in plastisch verformtem Calcit
Authors: Sterzel W. , Chorinsky E.
Published: March 2015

Farbzentren mit Absorptionen im Bereich des sichtbaren Lichtes entstehen bei Röntgen-Bestrahlung in Calcitkristallen, wenn die Kristalle durch Verformung eine hohe Störstellenkonzentration erhalten haben. Die Absorptionsspektren solcher Farbzentren werden ausgemessen und mit röntgenographisch bestimmten Störungsgraden verglichen. Die Bildung und die thermische Ausheilung der für die Entstehung von Farbzentren erforderlichen Störstellen wird quantitativ untersucht. Dabei wird festgestellt, daß mindestens zwei verschiedene Farbzentren auftreten, deren Konzentrationsverhältnis von der Temperaturvorbehandlung der gestörten Calcitproben abhängt.
Einfluß der Gasadsorption auf die Epitaxie dünner Metallschichten
Authors: Harsdorff Manfred
Published: March 2015

Special effects of gasadsorption on epitaxy were discussed in previous papers 1. In the present publication the influence of the adsorbed vapours on the epitaxial growth of fcc-metals on alkalihalides has been investigated in more detail. The results of the experiments demonstrate that the orientations of metal films are strongly influenced by the physical properties of the vapours the substrats are cleaved in. The thickness of the adsorbed layer is controlled by the dipole moment and the partial pressure of the vapours and additionnally by the substrat temperature and the deposition rate of the evaporated metal. Since the orientation of the metal films depends itself on the vapour covering of the cleavage planes, the orientation is also determined by these four quantities.
Nonequilibrium Effects in Recombination-Dissociation Kinetics II
Authors: Kolker H. J.
Published: March 2015

The selfconsistent theory of recombination-dissociation kinetics developed in an earlier article is derived in a more rigorous manner. A noniterative solution is obtained for the resulting equations describing the nonequilibrium distribution of the internal molecular energy levels. This method of solving these equations also leads to a number of interesting mathematical and physical insights about the importance of nonequilibrium effects in recombination-dissociation kinetics. Implicit in these equations is a method for calculating the vibrational relaxation times for both recombination and dissociation reactions. These same equations also arise in calculating the rate constant for a nontrivial model of a dissociating diatomic molecule. The mathematical techniques used to derive this information also allows us to show that the selfconsistent theory is really a generalization of the conventional steady-state approximation and a special case of a projection operator formalism for solving problems in nonequilibrium statistical mechanics.
Photochemical Reactions with Electron Transfer
Authors: Latowski Tadeusz
Published: March 2015

Quantum yields of hydrogen halide formation upon irradiation (λ=313 nm) of N,N-dimethylaniline together with different benzene halogen-derivatives in methanolic solution have been measured. In the discussion attention has been paid not only to relations between quantum yields of hydrogen halide and electron affinity of the acceptor, but also to the role of the interaction energy between transition moments in a heteropolar excimer.
Numerical Solution for the Forward Steady-State Behaviour of an Abrupt p+-n Junction
Authors: Sánchez M.
Published: March 2015

The forward steady-state behaviour of a one-dimensional abrupt p+-n junction germanium diode at zero and at low to high injection levels is analysed. For this purpose the numerical integration of the current differential equations, the continuity equations, and Poisson’s differential equation is performed not only inside the space-charge layer but also along the quasineutral regions of the diode satisfying the boundary and continuity conditions. The integration is made on a digital computer without applying the Boltzmann equilibrium approximation in the space-charge layer and the space-charge neutrality approximation in the quasineutral regions. Furthermore, the acoustical and optical mode scattering, the ionized impurity scattering, and the Hall-Shockley-Read and Auger recombination processes are included in the calculation. The method of solution applied differs from those already available in the literature and permits the “exact” computation of the space-charge density inside the relatively long (compared with the Debye length) quasineutral p and n regions of the diode considered. The numerical results for the hole and electron concentration distributions, the electric field distributions, the electron current density distributions, the electrostatic potential distributions and the space-charge density distributions are reported for five values of the total current density across the p-n junction. The comparison of the obtained numerical solutions with the closed analytical solutions for zero bias (as a test of the computer program) on the one side and of the computed current/voltage characteristic of the p-n junction with experimental values on the other side shows satisfactory agreement.
Zur Bandstruktur von Wismuttellurid
Authors: Drath P.
Published: March 2015

The analysis of Shubnikov-De Haas oscillations in n- and p-type Bi2Te3 indicate the existence of a multivalley structure of valence and conduction band. In p-type Bi2Te3 the surfaces of constant energy are found to consist of 6 ellipsoids. Spin splitting of the Landau-levels was observed, the anisotropy of the g-factor in the trigonal-bisectrix plane is consistent with an existing theory. In n-type Bi2Te3 Hall-coefficient, magnetoresistance and g-factor do not follow the predicted pattern of a simple many valley model, so that the number of ellipsoids could not be determined with certainty. The presence of an additional band must be considered.
Einfache Formeln zur Abschätzung von Coriolis-Kopplungskonstanten ζ. Zur Massenabhängigkeit von ζ -Werten
Authors: Kebabcioglu R. , Müller A.
Published: March 2015

Es werden einfache Formeln zur Berechnung von Coriolis-Kopplungskonstanten ζ für Moleküle des Typs XYm abgeleitet, mit deren Hilfe man die Massenabhängigkeit von ζ-Werten verstehen und für zahlreiche Moleküle, für die Masse (X) > Masse (Y) gilt, ζ-Konstanten abschätzen kann. Die theoretisch berechneten Werte werden mit experimentell bestimmten verglichen.
Excitonendiffusion in Naphthalin-Aufdampfschichten
Authors: Gallus G. , Wolf H. C.
Published: March 2015

Films of pure naphthalene and such doped with about 10-2 iodobenzene are evaporated. The diffusion length of singlet excitons in evaporated naphthalene is found to be 250 Å at 77 °K and 500 A at 170 °K. Besides the well known fluorescence of naphthalene the films show increasing emission from lattice defects with decreasing temperature. Therefore it is impossible to deduce the mechanism of exciton diffusion from the temperature dependence of the diffusion length. Energy migrates from naphthalene to anthracene guest molecules in an easier way than in single crystals. Surface quenching of singlet excitons in evaporated films is demonstrated.
Untersuchung der chemischen Verschiebung der 133Cs-Resonanz in synthetischen Zeolithen vom Faujasittyp
Authors: Lechert H. , Gunsser W. , Knappwost A.
Published: March 2015

The chemical shift of the 133Cs-resonance in dependence on water contents has been measured in two synthetic zeolithe samples of the Faujasite type. Referring to those filled with water, resonances of degassed samples showed a shift of 150 ppm. The chemical shift of saturated samples corresponds with the shift of a saturated solution of CsNO3. A comparison with similar theoretical and experimental investigation leads to the conclusion that the electronic system of the alumosilicate framework is not able to overlap with caesium ions and can be considered as highly polar in its adsorption properties.

Even in degassed zeolithe, caesium ions partially move in cavities.
Zur rotatorischen Bewegung eines Systems von n Massenpunkten. I
Authors: Ruder H. , Volz H.
Published: March 2015

The concept of rotational motion of a system of particles is strongly related to the existence of a frame of reference connected with the system in such a way that the coupling terms between the internal and the rotational motions vanish.

This frame of reference, if existent, has to be uniquely defined independent of the type of motion by the configuration of the system only.

It is shown that only in very special cases such a frame can be found. The existence of such a frame, however, is not sufficient for the appearance of a rotational structure in the energy spectrum of the system in quantum mechanical treatment. The importance of eliminating the coupling terms for the transition from the system of point masses to the limiting case of the rigid body is discussed. It is shown that in the case of exact decoupling the effective moments of inertia appearing in the Hamiltonian of the collective motion necessarily agree with the normal definition. It therefore seems inconsistent to neglect coupling terms and to take non-normal moments of inertia from the collective part alone.
Über Linear Passive Transformationen Stochastischer Prozesse I
Authors: Keller J.
Published: March 2015

The theory of linear passive systems, developed by KÖNIG and MEIXNER, is extended to the case where the input is not a well determined function of time but rather a stochastic process. In this case the answer of the system generally will also be a stochastic process. The input and output processes are connected by a linear passive transformation (LPT). Some examples are given of physical systems which may be described by LPT of stochastic processes. General properties of the mean value and the dispersion of the output process are derived.
Untersuchungen zur Epitaxie dünner Goldaufdampfschichten auf Alkalihalogeniden im Ultrahochvakuum
Authors: Adam R. W.
Published: March 2015

In the present paper the oriented growth of gold on alkalihalides, cleaved in ultra high vacuum has been investigated. The dependence of the crystal orientation on the deposition parameters substrate temperature, deposition rate, and the physical properties of the substrate were studied systematically. At suitable substrate temperatures and deposition rates it was possible to obtain epitaxial gold films on KCl, KBr and KJ.
Messungen und Berechnungen zum elektronenmikroskopischen Streukontrast für 17 bis 1200 keV-Elektronen
Authors: Reimer L. , Sommer K.H.
Published: March 2015

Electron transmission experiments under electron microscope conditions were done with C-, Ge- and Pt-films to get information about the influence of electron energy and objective aperture. One gets an exponential law of transmission for small mass thicknesses x of the objects and can calculate the “contrast thickness” xk (in T = exp(— x/xk)). Using the Lenz theory, two constants Xa and ϑ0 are determined, for each element and electron energy, from the measurements of xk at four different objective apertures. xa is related to the total elastic scattering cross section and ϑ0 is the half width of the atomic scattering amplitude ƒ(ϑ). The variation of xa and ϑ0 with electron energy is not in agreement with the theory using the first Born approximation and a simple screened atomic potential. But using these two experimentally determined constants in a plural scattering theory of LENZ, good agreement between calculated and experimental deviations from the exponential law of transmission up to mass thicknesses of 300 µg · cm-2 is obtained.

To get better theoretical values of xk, the complex atomic scattering amplitudes were calculated quantum theoretically with the WKB-method and Hartree potentials. The values agree with the experimental results for Ge- and Pt-films. For carbon there is a large contribution by inelastic scattering making a direct comparison with experimental results difficult.

The energy dependence of xa shows saturation for high voltages, as expected by theory. At high voltages the difference in the xk-values for films with different atomic numbers is larger, resulting in lower xk-values for platinum. But at very low voltages the xk-values of carbon are lower than those of platinum. Some measurements of xk at 60 keV on targets of noble gases confirm the absence of a large difference in contrast between atoms in the gaseous and condensed amorphous state.
Die Beeinflussung der optischen Absorption von Molekülen durch ein elektrisches Feld
Authors: Liptay W. , Schlosser H.-J. , Dumbacher B. , Hünig S.
Published: March 2015

Aus elektrooptischen Absorptionsmessungen und dielektrischen Messungen an Lösungen von Farbstoffmolekülen können die Dipolmomente der Moleküle im Elektronengrund- und einigen niedrigen Anregungszuständen, die Übergangsmomentrichtungen und bestimmte Komponenten des Tensors der Übergangspolarisierbarkeit ermittelt werden. Diese Größen bestimmen die Solvatochromie der Farbstoffe, d. h. die Lösungsmittelabhängigkeit der Lage und der Intensität der Absorptionsbanden.

In der vorangehenden Arbeit wurde über elektrooptische und dielektrische Messungen an sechs Farbstoffmolekülen berichtet. Von vier dieser Farbstoffe wurde die Solvatochromie ausführlich untersucht. Die Lösungsmittelabhängigkeit der Lage der Absorptionsbanden bestätigt frühere theoretische Modelle. Die Lösungsmittelabhängigkeit der Intensität ermöglicht eine unabhängige Bestimmung einer Komponente des Tensors der Übergangspolarisierbarkeit; die Ergebnisse sind in Übereinstimmung mit den aus elektrooptischen Messungen erhaltenen Werten.

Bei einem der Farbstoffe wurde ein extrem großer Wert für eine Komponente der Übergangspolarisierbarkeit gefunden, was eine extrem starke Lösungsmittelabhängigkeit der Intensität der Bande zur Folge hat. Der maximale Extinktionskoeffizient der Bande ist in Tetrachlorkohlenstoff 33 900, in Diäthyläther 52 300 und in Acetonitril 168 000. Die theoretischen Beziehungen erlauben eine Extrapolation auf den Gaszustand, in welchem der Extinktionskoeffizient nicht viel von Null verschieden sein wird. Demnach gibt es in diesem Molekül eine Absorptionsbande, die im freien ungestörten Molekül nur sehr schwach ist, durch eine Störung durch ein elektrisches Feld aber außerordentlich intensiv werden kann.
Notizen: Experiment on the Isotropy of Alpha-Alpha Angular Correlation in the Serial Decay of 228Th and 226Ra
Authors: Biswas M. M. , Gupta B. K. , Sen P. K. , Bhattacharya P. C.
Published: March 2015

Experiment on the angular correlation between consecutive alphas emitted in the serial decay of 228Th and 226Ra are performed on the stars produced in emulsion. The correlation distributions follow isotropy.
Messung der Absorptionsoszillatorenstärken von SI- und S II-Linien im Bereich zwischen 1100 und 2000 Å
Authors: Müller Dragutin
Published: March 2015

The absorption oscillator strengths of 44 S I- and 9 S II-lines between 1100 and 2000 Å are measured in emission. The light source is a wall-stabilized arc burning in definite argon-SF6 mixtures. Normal-intensities are produced by the same source. The evaluation of particle densities is carried out without assuming constancy of mixture ratio and knowledge of any transition probability.
Einfluß einer Ionenpaarbildung auf das ESR-Spektrum von durch photochemische Elektronenübertragung erzeugten Radikalionen
Authors: Briegleb G. , Lind G.
Published: March 2015

The ESR-spectra recorded during irradiation (436 mµ) of solutions of nitrobenzene, o-, m-, p- dinitrobenzene, and trinitrobenzene in tetrahydrofuran exhibit a hyperfine pattern which can be derived from the negative radical ion of the nitro- and polynitro aromatic compounds in ion-pairs with the n-donor cation (e. g. THF·+), generated by a transfer of an electron from the donor molecule to the acceptor molecule. Owing to the strong interionic interaction of the radical ions in the ion-pairs the photoinduced ESR spectra are quite different from the ESR spectra produced by electrolytic reduction of nitrobenzenes. The ESR spectra may be explained by a strong coupling of the donor cation (THF+, dioxane+, diphenylether+, or di-tert.-butylether+) with the 14N nucleus of a single dominant NO2-group. The nonequivalence of the NO2-groups in the photoinduced radical ion-pairs between nitrobenzenes and n-donor cations is more significant than in ionpairs between an alkali-metal ion and nitrobenzenes, owing to the small size of the radius of Ol
+ (ca. 0.9 Å) in the donor cation (e. g. THF·+). The ESR spectra of nitrobenzene- and trinitrobenzene- in ion-pairs with THF+ or dioxane+ yield an additional small splittitng constant (0.22 to 0.44 G) according to an interionic coupling interaction with an α-proton of THF·+ in the ion-pair. A hydrogen transfer from THF to a NO2-group (WARD 2) has not been established with certainty and needs not to be taken into account from some points of view. The THF·+ signal becomes undetectable because of an electron exchange THF·++THF ↔ THF+THF·+, since there is a large excess of THF molecules. Quantitative details of the change of the signal-intensity during irradiation, and of the influence of temperature will be published in a following publication.
ESR-Untersuchungen zur Radikalbildung in röntgenbestrahlten zinnorganischen Verbindungen
Authors: Höppner K. , Lassmann G.
Published: March 2015

Formation of radicals in tin-organic compounds of the type R4Sn (R : CH3, C2H5, C2H6, Cl, Br) as well as (CH3)3SnCl and (CH3)3Sn—Sn(CH3)3 irradiated with X-rays at 77°K has been investigated by ESR. The change of spectra after stepwise annealing of the sample shows that a least two types of radicals are present. In some cases trivalent tin radicals R′ (CH3) 2Sn (R': CH3 or Sn (CH3)3) with an unpaired electron localized at the Sn atom with g=2.02 have been detected. A further radical of the type ≡Sn —CH2 with a tin hyperfine structure of 132 and 160 Gauß resp. has been identified by the hyperfine structure of the magnetic 117Sn- and 119Sn-nuclei. A mesomeric stabilized radical in (C6H5) 4Sn is unusually stable, as the ESR spectrum did not change from 77°K till 423°K. The yield of radicals in (C6H5) 4Sn is smaller by two orders of magnitude than in aliphatic tin-organic compounds.
Mikrowellenspektrum und Struktur von Fluortribromsilan und Methyltribromsilan
Authors: Mitzlaff M. , Holm R. , Hartmann H.
Published: March 2015

The microwave spectra of SiFBr3 and CH3SiBr have been investigated in the region from 30 to 40 GHz. Assuming reasonable values for dSi-F, dSi-C and the methyl group a least squares analysis of the rotational constants yields

dSi-Br ≮Br—Si—Br

SiFBr3 (2,171 ± 0,001) A (111,36 ± 0,15)°,

CH3SiBr3 (2,175±0,001) A (111,09±0,15)°.

A barrier to internal rotation of about 1 kcal/mole is estimated by the intensity method.
Zur Elektrodynamik turbulent bewegter leitender Medien
Authors: Rädler K.-H.
Published: March 2015

This paper deals with the behaviour of electromagnetic fields in electrically conducting media carrying out turbulent motions. The basis is formed by Maxwell’s and the corresponding constitutive equations inclusive Ohm’s law, all with the neglections usual in magnetohydrodynamics. Attention is directed to certain mean fields defined by statistical averaging.

From the equations mentioned above, except Ohm’s law, one gets equations of the same kind for the mean fields. In Ohm’s law, however, the transition to the mean fields leads to an additional term

, the averaged vector product of the fluctuations in the velocity of the medium and the magnetic flux density. The investigation of this term makes up the centre in the elaboration of an electrodynamics of mean fields.

As a very simple example a homogeneous isotropic turbulence showing reflexion symmetry is considered. In this case

makes allowance for the introduction of a modified electrical conductivity. If the reflexion symmetry is violated,

describes an effect allowing a dynamo action.

Furthermore, a general method for calculation of

for arbitrary turbulent motions is developed, and a survey is given of the results which can be expected for some special kinds of turbulence.
Zur Elektrodynamik turbulent bewegter leitender Medien
Authors: Rädler K.-H.
Published: March 2015

In a foregoing paper the foundations for an electrodynamics of mean fields in turbulently moving electrically conducting media were developed. With the method demonstrated there a special case is treated. The turbulence is supposed to deviate from a homogeneous isotropic one showing reflexion symmetry, only due to a gradient of intensity, i. e. of the mean square velocity. The calculations are carried out for small intensities. As a result, expressions for the modified conductivity introduced for homogeneous turbulence in the foregoing paper are given and discussed. The effect of the intensity gradient is illustrated by a simple example. Furthermore, a possibility is shown for describing the general result in terms of modified conductivity and permeability.
Messungen der Elektronenbeweglichkeit bei hohen Gasdrucken in Ar, He, N2 und H2
Authors: Grünberg R.
Published: March 2015

By means of a time of flight method the electron drift velocity ν _ in argon, helium, nitrogen, and hydrogen was determined as function of E/p [V/Torr cm] at room temperature and for high pressure up to 42 at, at which no measurements were as yet available. In He and H2 E/p was decreased to that range where the electrons are in thermal equilibrium with thet gas. In N2 measurements were extended nearly to this range, and in Ar measurements were carried out for E/p well above this range of thermal equilibrium.

The accuracy from 1% to 1.5% in the available pressure range enabled an examination of the similarity rule. For the diatomic gases N2 and H2 the measurements show that for constant E/p, in the range E/p < 1, the drift velocities decrease with increasing pressure. This effect was not found in Ar. In He no effect was found in the pressure range up to 8400 Torr (or it lies within the limits of error).
Viskosimetrische Untersuchungen zum Schmelzprozeß von Metallen am Beispiel des Galliums und der intermetallischen Verbindung Hg5Tl2
Authors: Predel B. , Arpshofen I.
Published: March 2015

Zur viskosimetrischen Verfolgung des Schmelzvorganges von Metallen wurde ein Schwingtiegelviskosimeter konstruiert, das es gestattet, die Viskosität von Schmelzen, die frisch aus dem Festkörper entstanden sind, rasch und präzise zu messen. An hochreinem Gallium konnte ein viskosimetrischer Nachschmelzeffekt festgestellt werden, der darin besteht, daß die Viskosität der unmittelbar aus dem Kristall entstandenen Schmelze anomal hoch ist und innerehalb von etwa 1 min auf den üblichen Viskositätswert der Gleichgewichtsschmelze abfällt. Das Abklingen der überschüssigen Viskosität ist irreversibel. Beim Abkühlen des flüssigen Galliums bis unter seinen Schmelzpunkt tritt kein anomaler Anstieg der Viskosität ein. In ähnlicher Weise ist auch das Schmelzverhalten der Verbindung Hg5Tl2 untersucht worden. Hier tritt kein Nachschmelzeffekt auf.

Das unterschiedliche Verhalten der beiden untersuchten Substanzen ist auf die individuellen Änderungen der Bindungs- und Strukturverhältnisse beim Übergang fest—flüssig zurückzuführen. Beim Gallium treten am Schmelzpunkt unmittelbar nach der Auflösung des Gitters offenbar größere, nicht im Gleichgewicht befindliche Agglomerate auf. Erst nach deren Dissoziation ist die Gleichgewichtsstruktur der Schmelze erreicht. Unter idealisierenden Annahmen kann aus der Viskositätsüberhöhung beim Nachschmelzeffekt ein Clusteranteil an der Gesamtschmelze von größenordnungsmäßig 10% abgeschätzt werden.
Temperature and Solvent Dependence of 13C—H Spin-Spin Coupling Constant JCH in Ethyl Formate
Authors: Rahkamaa Erkki , Jokisaari Jukka
Published: March 2015

PMR spectra of pure ethyl formate and its solutions in carbon tetrachloride, carbon disulfide and acetone indicate that both the directly bonded 13C—H coupling constant and the chemical shift of the formyl group vary with temperature, solvent and concentration. Some aspects of the temperature and solvent dependence of JCH and δ can be related to the intermolecular hydrogen bonding involving the formyl proton. The possibility of the existence of other factors must however not be forgotten.
Experimental Effects of R.F. Irradiation on N.M.R. Lines in Solids Dynamics of the Equilibrium Establishment
Authors: Steenwinkel R. Van
Published: March 2015

The rates of dipolar and Zeeman energy creation under detuned irradiation are measured as function of the distance to resonance in isolated spin systems and in systems with known coupling to the lattice.

The experimental results are compared with the Provotorov theory and, with some restrictions for the long correlation time region, the agreement with theory is found to be excellent.