bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solution of the Dirac Equation for the Rectilinear Periodic Motion of an Electron
Authors: Jannussis A. D. 
Published: February 2015

Abstract
In this paper the Dirac equation for a rectilinear onedimensional periodic potential is treated. It is shown that the energy eigenvalues are periodic functions of the wave number Kϰ and the continuous spectrum is split into energy bands. The end points of the energy bands are the points where the Bragg reflection takes place.
These results are obtained by perturbation theory, as well as by the method of determinants, since the resulting eigenvalue equation has the form of a determinant which is similar to the Hill determinant.
Zufallswege und Reaktionen atomarer Gitterfehler in Modellkristallen
Authors: Mehrer Helmut 
Published: February 2015

Abstract
Random walks and reactions of point defects in face-centered cubic lattices have been simulated by means of a Monte-Carlo method described in the preceding paper (I) . In this paper the method is applied to the recombination of vacancies and interstitials. Equal or different numbers as well as random or correlated initial distribution of vacancies and interstitials are considered. The inter­ action between the defects is taken into account by a model for the pair volume surrounding a vacancy.
Untersuchungen an Thermoketten
Authors: Haase R . , Richter J. 
Published: February 2015

Abstract
Es werden Thermoketten betrachtet, die zwei Elektrolyte mit insgesamt drei Ionenarten in ge­schmolzenem Zustand enthalten. Mit Hilfe der Methoden der Thermodynamik der irreversiblen Pro­zesse lassen sich die allgemeinen Ausdrücke für den Anfangswert und den Endwert der Thermokraft einer solchen Thermokette gewinnen. Die aus den Messungen bestimmbaren charakteristischen Größen sind die beiden Überführungsentropien der den Elektrolyten nicht gemeinsamen Ionenarten, gemessen relativ zur gemeinsamen Ionensorte. Die entsprechenden Formeln für Thermoketten mit reinen flüssigen Elektrolyten lassen sich als Grenzfälle ableiten. Messungen von Sundheim und Kellner an Thermoketten, kombiniert mit anderen Literaturdaten, ergeben die Überführungsentropien der Natrium-und Silberionen für die binäre Schmelze NaNO3+ AgNO3 in Abhängigkeit von der Zusammensetzung bei 310 °C. Anhangweise werden die Konsequenzen eines einfachen Ansatzes für die Uberführungszahlen, wie er für NaNO3 + AgNO3 zu gelten scheint, besprochen. Dabei wer­ den auch Konzentrationsketten behandelt.
Begründung der Lorentz-Gruppe allein mit Symmetrie-und Relativitäts-Annahmen
Authors: Süssmann G. 
Published: February 2015

Abstract
Aus dem Relativitätsprinzip folgt ohne Verwendung des empirischen Prinzips von der Konstanz der Lichtgeschwindigkeit, daß die Lorentz-Transformation die einzig denkbare Alternative zur (raumzeitlich asymmetrischen) Galilei-Transformation ist.
Zur Struktur der Graphit-Eisen(III)-chlorid-Einlagerungsverbindungen
Authors: Knappwost A. , Grigutsch F. D. 
Published: February 2015

Abstract
Die allgemein übliche Charakterisierung gewaschener Graphit-Eisen(III)-chlorid-Einlagerungsverbindungen nach ihrem Eisenchloridgehalt allein ist unzureichend, weil die aus gesättigten Verbindungen eluierte Eisenchloridmenge eine Funktion der Teilchengröße der Graphitkristalle ist. Diese Ergebnisse stützen die zuerst von Rüdorff und Landel beschriebenen Anschauungen, daß nach Eluieren des Eisenchlorids in den Randzonen die Graphitstruktur zurückgebildet wird. Dadurch wird das Kristallinnere vor einem weiteren Lösungsmittelangriff bewahrt, und die Struktur der ersten Verbindungsstufe bleibt dort erhalten..
Der bisweilen beschriebene Unterschied zwischen Natur- und Synthesegraphit im Eisenchlorid-Maximalgehalt gewaschener Einlagerungsverbindungen läßt sich ebenfalls durch die Teilchengrößenfunktion erklären und braucht nicht auf die unterschiedliche Herkunft der Graphite zurückgeführt zu werden.
In dem vom Lösungsmittel nicht angegriffenen Verbindungskern sind ca. 40% der verfügbaren Schichtfläche nicht mit Eisenchlorid besetzt. Dichtemessungen und Röntgen-Untersuchungen ergeben, daß die Kohlenstoffschichten in diesen Bereichen nicht aufgeweitet sind, sondern den gleichen Schichtabstand wie der reine Graphit aufweisen. Aus der Linienschärfe der Röntgenreflexe folgt, daß die Ausdehnung der kohärenten Bereiche mit Graphitstruktur in c-Richtung im Mittel über 800 Å beträgt. Der für Graphit typische anomale Diamagnetismus tritt bei den Einlagerungsverbindungen trotz dieses Graphitanteils nicht auf.
Bestimmung der Halbwertszeit von 210Pb
Authors: Höhndorf A. 
Published: February 2015

Abstract
The half-life of 210Pb has been calculated from measurements of the specific activity and the 210Pb-concentration of a 210Pb-solution. The specific 210Pb-activity was determined by measuring the daughter product 210Po using an α-spectrometric isotope dilution method with 208Po as tracer. The 210Pb-concentration was measured by mass-spectrometric isotope dilution analysis. A half-life of 22.26 ± 0.22 ( = 2 σ) years has been obtained.
Negative magnetische Widerstandsänderung von ZnSb
Authors: Peters F. , Schneider G. 
Published: February 2015

Abstract
ZnSb zeigt wie einige andere Halbleiter bei tiefen Temperaturen die eigenartige Erscheinung einer negativen magnetischen Widerstandsänderung, d.h. eine Abnahme des elektrischen Widerstandes im Magnetfeld. Die Größe dieses Effektes wurde in Abhängigkeit vom Magnetfeld H und von der Ladungsträgerkonzentration p untersucht. Für das Auftreten der Erscheinung können Grenzen in bezug auf p und H angegeben werden. Die Messungen an einkristallinem und polykristallinem Material zeigen unterschiedliche Resultate. Die Ergebnisse werden vor allem in bezug auf verschiedene Komponentenzerlegung in positive und negative Anteile der Widerstandsänderung
diskutiert.
Calculation of the Centrifugal Distortion Constants Using Dependent Internal Coordinates, Numerical Example Cyclopentene
Authors: Petzuch M. 
Published: February 2015

A formula is derived for the calculation of the centrifugal distortion constants ταβγδ in the case where the vibration problem is solved by using dependent internal symmetry coordinates. We have calculated the τ’s and the D's with this new formula for a model of cyclopentene with a planar carbon ring (Point group C2v).
The τ-values calculated are (in units 1085 sec2 (gem2)-3):
τxxxx = - 5.27, Txxyy = 1.48, τxxzz = - 0.96,
τyyyy = - 5.52, Tyyzz = - 1.22, Tzzzz = - 0.63,
τxyxy = - 2.85, Tyzyz - 0.07, Tzxzx = - 0.07.
The D's calculated are (in units 10-8 cm-1):
DJ = 7.9, DK = 5.1, DJK = - 12.1.
The values for DJ and for DJK are within the accuracy of the published experimental values.
Thus, cyclopentene is the first ring molecule, the centrifugal distortion constants of which could be calculated.
Notizen:Eine Gasmischung aus Argon und Stickstoff als Füllung für α-Proportionalzählrohre
Authors: Heye Dietrich 
Published: February 2015

Abstract
A counting gas has been tested which can be used for α-proportional counting at high temperatures (700 °C). A mixture of 13 parts Ar and 1 part N2, is stable at a pressure of 700 mm Hg. The counter has a plateau of more than 100 Volts with low slope. The stability which has been tested for a period of 55 hours and 108 counted pulses proved to be satisfactory.
Notizen:Estimation of Electric Polarizabilities of Organic π-Electron Systems from Kerr Effect Measurements
Authors: Schweig A. 
Published: February 2015

Abstract
A method to estimate the principal polarizabilities of π-electron clouds embedded in a continuous uniform medium of dielectric constant ε0 = 2 is described and applied to deter­mine these polarizabilities in the case of aromatic hydro­carbons.
Das Mikrowellenrotationsspektrum des PbTe
Authors: Tiemann E. , Hoeft J. , Schenk B. 
Published: February 2015

Abstract
Im Frequenzbereich 11 - 15 GHz wurden bei Temperaturen um 680 °C die Rotationsübergänge J = 5 → 6 und J = 7 → 8 von 16 isotopen Molekeln des PbTe gemessen. Es werden Rotationskon­stanten, Kernabstände und Koeffizienten der Potentialfunktion nach Morse sowie Massenverhält­nisse von Blei- und Tellurisotopen mitgeteilt.
Abklingzeitmessungen an Pseudoisocyanindiäthylchlorid mit einem Phasenfluorometer mit 200 MHz-Lichtmodulation
Authors: Michelbacher E. 
Published: February 2015

Abstract
The decay time of pseudo-isocyanine (2,2 nsec at room temperature) has been measured by a phase fluorometer of 200 Me modulation frequency and its temperature dependence with respect to self absorption has been investigated. This allows to calculate the molecular decay time (1,7 nsec) and the number of molecules, which form the fluorescent polymer of the dye. Moreover the decay times of some p-oligophenylenes and the quenching effekt of nitrobencene on POPOP (1,82 nsec) have been measured.
Zur anodischen Bildung von Silberoxiden
Authors: Gossner K. , Eftychiadis Th. , Körner D. 
Published: February 2015

Abstract
Die anodische Oxydation von Silber wurde in alkalischem Milieu (0,01-n. NaOH) galvanostatisch und potentiostatisch verfolgt, und parallel dazu wurde die Bildung der Oxidphasen durch Elektronen­beugung untersucht und den Ladekurven zugeordnet. Die Ladekurven zeigen bei galvanostatischer Versuchsführung unabhängig von der vorgegebenen Stromdichte einen gleichartigen Verlauf; bei potentiostatischer Versuchsführung verlaufen sie je nach Polarisationsbereich verschieden. Sowohl bei galvanostatischer als auch bei potentiostatischer Oxydation wird stets die Bildungsreihenfolge Ag → Ag2O → AgOx → AgO gefunden. Im Bereich der beginnenden Sauerstoffentwicklung tritt manchmal Ag2O3 auf.
Zur anodischen Bildung von Silberoxiden
Authors: Gossner K. , Eftychiadis Th. , Körner D. 
Published: February 2015

Abstract
Bei der Untersuchung anodisch oxydierter Silberelektroden durch Elektronenbeugung werden die folgenden Oxide gefunden: das kubische Ag2O, das "AgOx" mit kubisch-flächenzentriertem Ag-Teil-gitter und das monokline AgO. Auf einigen Beugungsaufnahmen wurde das kubische Ag2O3 identi­ fiziert. Die jeweilige Oxidschicht auf den Silberelektroden erweist sich bei Abtragung durch Ionen­ ätzung als einheitlich. Die Zuordnung der einzelnen Oxidphasen zu den entsprechenden Bereichen der galvanostatischen Ladekurve ermöglicht eine Deutung des zeitlichen Potentialverlaufs während der Oxydation. Der je nach angelegter Polarisation unterschiedliche Verlauf der potentiostatischen Ladekurven läßt Rückschlüsse auf den jeweils vorherrschenden Oxydationsmedianismus zu.
The Phase Diagram of the System Li2SO4 — K2SO4 from Differential Thermal Analysis
Authors: Schroederand Kjell , Kvist Arnold 
Published: February 2015

The phase diagram of Li2SO4-K2SO4 has been determined by differential thermal analysis. By making use of ail improved method, the sensitivity of the measurements has been increased and we have found a number of new transitions, especially in the lithium sulphate rich region. We have also detected a new transition in LiKSO4 at 672 °C. The new transitions have lead to an unusually complicated phase diagram compared with other sulphates. Some of the results have been checked bv measuring the electrical conductivities of the phases.
XFA (9014)
Das Fluoreszenzspektrum von Anthracen-Kristallen
Authors: Glöckner E. , Wolf H. C. 
Published: February 2015

The fluorescence spectrum of extremely purified and good anthracene crystals has been re­measured. It is compared with the exciton band structure as calculated by Davydov and Sheka. The origin of the intrinsic fluorescence is at 25 097 cm-1. This is the lower edge of the exciton band with k ≠ 0. Therefore this 0.0-transition is forbidden. The allowed 0.0.transition of the lower Davydov component of the exciton band is observed at 25 298 cm-1 with very low intensity. This is the position of the very short living state k = Q (Q=photon wave vector) in the exciton band. Further observations concerning the structure and temperature dependent width of emission lines, the nature of exciton-phonon and exciton-vibron coupling and the large band width in absorption are also in good agreement with the calculated band structure.
The polarization ratio of the strongest vibronic transitions is 7.5 ± 1 good agreement with the oriented gas model. The spectral region near the forbidden 0.0-transition is completely 6-polarized. Effects of defects in the spectrum (series of lines due to impurities and X-traps, continuous back­ground) were widely eliminated. They are discussed here only as far as necessary for a better understanding of the unperturbed crystal spectrum.
In an appendix a list of 154 fluorescence lines is given.
Functional Quantum Theory of Scattering Processes I
Authors: Stumpf H. 
Published: February 2015

Abstract
Dynamics of quantum field theory can be formulated by functional equations. To develop a com­plete functional quantum theory one has to describe the physical information by functional opera­tions. One of the most important physical information of elementary particle physics is the S-matrix. To derive a functional expression for this quantity the potential scattering model is studied. A func­tional S-matrix is defined and its equivalence with the ordinary S-matrix definition in physical Hilbert space is proven. Also a calculational method for scattering functionals is proposed. In the appendices technical details are discussed.
Messungen des Anlagerungskoeffizienten von Elektronen in Sauerstoff
Authors: Grünberg R. 
Published: February 2015

Abstract
The attachment coefficient η for the formation of negative ions in low energy electron swarms was measured over an E/p-range of 0.1 ... 30 V/Torr cm by a new and accurate method. Thus earlier measurements up to 54 Torr of other authors could be extended to 880 Torr.
The shape of the minimum in the η/p-curves between the three-body process (e+2O2 → O2
- + O2) and the dissociative process (e + O2 → O- + O) and its shift to higher E/p with increasing pressure was measured. Behind the minimum a maximum at E/p = 14 was found. Between the minimum and this maximum the dissociative process is predominant but the three-body process is still of influence. For E/p > 14 the η/p-values are slowly decreasing with increasing E/p.
For the higher pressures above 44 Torr deviations from the relation η proportional to p2 were found for the three-body process. These deviations are discussed.
Absorptionsspektroskopie an resonanzverbreiterten Atomlinien zur Dichtemessung in Düsenstrahlen
Authors: Brunner W. 
Published: February 2015

Abstract
Die Absorptionsspektroskopie an resonanzverbreiterten Atomlinien wird als einfaches und genaues Meßverfahren beschrieben, das vor allem für Untersuchungen an Zweiphasengemischen geeignet ist, bei denen ein Anteil aus Metalldampf besteht. Die zum Verständnis notwendige Theorie wird kurz skizziert und ein Anwendungsbeispiel beschrieben. Dabei handelt es sich um eine Zweiphasenexpansion ins Vakuum, die mit einer Metallverdampfung verbunden ist.
Kernrelaxation und Quanteneffekte bei der Methylgruppenrotation von festem Toluol und Toluolderivaten
Authors: Haupt J. , Müller-Warmuth W. 
Published: February 2015

Abstract
The hindered rotations of methyl groups have been studied in solid toluene, 2-F-toluene and 3-F-toluene. NMR pulse investigations have been carried out between the melting point and liquid helium temperatures at 14.5 MHz and 40.7 MHz. As in the case of earlier studies on the three xylenes, which have been continued in this work, the motional narrowing of the proton resonance lines was found to persist down to very low temperatures. In comparison with their exponential increase at high temperatures, the spin-lattice relaxation rates 1/T1 decay as a function of reciprocal temperature much less rapidly in the low temperature range. In the transition region, 1/T1 exhibits maxima which are more or less broadened or distorted. In effect, the relaxation at low temperatures is much stronger than that predicted by semiclassical theories.
An explanation of the observed behaviour takes into acount the quantization of the rotational and torsional motion and the coupling between the spin and rotational degrees of freedom on one hand, and the phonons of the lattice on the other hand. At low temperatures, the motion causing nuclear spin-lattice relaxation is reduced to certain torsional transitions between the lowest states, which are connected with tunneling. At high temperatures, the summation of a great number of rotational transitions in the presence of strong coupling to the lattice leads o the "classical" behaviour.
The potential barriers hindering the methyl group reorientations were found to be rather small in all the materials studied: toluene 0.1-0.2 kcal/mole, 2-fluorotoluene 0.50 kcal/mole, 3-fluoro-toluene 0.30 kcal/mole. They are, however, still large in comparison with free molecule data.
Proton Magnetic Resonance Study of Mercury Dimethyl in a Nematic Liquid Crystal
Authors: Englert Gerhard 
Published: February 2015

Abstract
The P.M.R.-spectrum of mercury dimethyl partially oriented in a nematic liquid crystal has been studied. From the ratio of the direct magnetic dipole-dipole interactions of the protons the ratio ξ0/ρ is calculated. ξ0 being the distance of the two parallel planes containing the methyl protons, and ρ being the distance of the methyl protons from the molecular symmetry axis. From this ratio the splitting due to the direct coupling of the protons with 199Hg of spin 1/2, present in about 17% natural abundance, is calculated and compared with the experimentally observed one. Exact agreement is obtained under the assumption that the methyl groups are rapidly rotating and that the direct and indirect 199Hg-H-couplings have like signs. Since the preferred orientation of the long axis of mercury dimethyl is probably parallel to the direction of the magnetic field, the absolute sign of J199Hg, H is found to be negative. Correspondingly it is shown that the sign of JCH3, CH3 is positive. No evidence is found for a possible contribution of the anisotropic part of the indirect couplings.
Nullfeld-Elektronenspinresonanz im Frequenzbereich von 10 MHz bis 200 MHz
Authors: Birkle M. , Geiger A. , Schoffa G. 
Published: February 2015

Abstract
Im Frequenzbereich von 10 MHz bis 200 MHz werden mit der Methode der Hfs-Nullfeldresonanz Hyperfeinstrukturaufspaltungen untersucht. Es handelt sich dabei um Elektronenspinresonanz im Feld eines oder mehrerer Kernspins ohne äußeres Magnetfeld. Die Aufspaltung der Elektronen-niveaus auf Grund von Elektronenspin-Kernspin-Wechselwirkung führt für Radikale, die durch Bestrahlung organischer Substanzen entstehen, meist zu Spektren mit Übergangsfrequenzen bis zu ca. 200 MHz. Es wird kurz der Aufbau und die Wirkungsweise des Nullfeldspektrometers beschrie-ben. Die Anwendungsmöglichkeiten der Hfs-Nullfeldresonanz werden an Hand der Bestimmung der Hyperfeinstruktur-Kopplungkonstanten an bestrahlten organischen Radikalen erläutert, wobei ge-zeigt wird, daß die Hfs-Nullfeldresonanzspektren zur Klärung der Veränderungen der Substanzen durch Bestrahlung wesentlich beitragen.
ESR-Untersuchung der behinderten Rotation der CH2-Gruppe im photolytisch erzeugten H2C — CO — CH3-Radikal
Authors: Golde G , Möbius K , Kaminski W 
Published: February 2015

Abstract
The radical H2C -CO -CH3 was produced in an acetone/H2O/H2O2 solution by photolysis using techniques similar to those developed by LIVINGSTON and ZELDES. The temperature dependence of the ESR spectrum indicates restricted rotation of the CH2-group relative to the rest of the molecule. A complete line-shape analysis of the spectrum at various temperatures leads to Arrhenius-para-meters Ea= (9.4 ± 0.5) kcal/mol and 10log k0 = 12.9 ± 0.3 which can be interpreted in the frame of the simple HMO theory.
Mössbauer-Effekt von 57Fe und 119Sn in Palladiumlegierungen verschiedenen Wasserstoff-Gehaltes
Authors: Mahnig M , Wicke E 
Published: February 2015

Abstract
The isomer shifts of 57Fe and 119Sn in Pd/Fe and Pd/Sn alloys of different compositions have been studied as functions of hydrogen content. In both systems the isomer shifts start to increase steeply at hydrogen contents which bring up the electron concentration in the alloy to 0.55 additional electrons per metal atom (compared to pure Pd). In accordance with results from other experimental methods each Fe atom has been found to donate 3 and each Sn atom 3.5 electrons to the bands of the alloy. The increase of the isomer shift is shown to follow the rise of the Fermi level when the bands are filled up gradually. It can be correlated to Friedel's model of virtual bound states.
The results obtained confirm the connections developed earlier between the absorption of hydro-gen and the electronic structure of Pd and its alloys. They agree with conclusions drawn from magnetic behaviour and from electronic specific heats at low temperatures. They do not verify, how-ever, a direct relation to the lattice constants in these systems. It is not yet obvious how to correlate our results with the value of 0.36 d-holes in pure Pd obtained recently from measurements of the de Haas-van Alphen effect; possible deviations from the rigid-band model are discussed.
Emission from Excited Terminal States of Bound Exciton Complexes
Authors: Reynolds D.C. , Collins T.C. 
Published: February 2015

Abstract
Emission from the excited terminal states of bound exciton-donor complexes has been observed in several II-VI compounds. Studying these optical transitions allows one to determine the donor ionization energies, the electron effective masses as well as the electron g-values in these materials. A good theoretical fit to the experimental data was obtained, using the effective mass approximation. Emission from the excited terminal states of bound exciton-acceptor complexes has not yet been observed in these materials. There is no basic reason why such transitions should not occur. Studying transitions of this type would allow one to obtain fundamental information concerning the acceptor impurities in these materials.
Untersuchungen an Chrom-Leuchtzentren in Magnesiumtitanat
Authors: Dittmann R. , Hahn D. , Stade J. 
Published: February 2015

Chromium activated powdery Mg2TiO4 was prepared using the oxides MgO and TiO2 with LiCl as a flux. The preparation was realized by two annealing processes one after another at 850 °C and 1400 °C for activated specimens and for samples without activator.
The excitation spectra were measured at room temperature and 77 K. The difference in remission was investigated at 293 K for activated samples and specimens without chromium and also the difference in absorption for the same samples.
The excitation-, remission- and absorption spectra show three peaks with a different behaviour if the activator concentration increases. Therefore the chromium luminescence centres in the Mg2TiO4 prove to be Cr3+-ions surrounded by six oxygen ions and chromium clusters respectively. The assumption of two different luminescence centres is supported by the results of the emission spectra.
An energy transfer exists between these two types of centres and depends on the activator concentration.
Investigation of Low Density Supersonic Jets by Means of a Molecular Beam Sampling Technique
Authors: Eckelt W. , Hose H. , Schügerl K. 
Published: February 2015

The performace of a supersonic molecular beam equipment is described. Velocity distributions of the particles in low density supersonic jets consisting of Helium, Argon, Methane and/or Ethane were measured by means of a molecular beam sampling technique and a multi-disc velocity analyser. The jets were produced by expanding the gas from an oven with stagnation pressures of 5 to 5000 torr and temperatures of 293 to 950 °K across different converging nozzles into a vacuum chamber.
The Mach numbers as functions of the source Knudsen numbers were calculated using the source flow theory of Sherman and the hypersonic approximation for the translational nonequilibrium of Hamel-Willis and Edwards-Cheng. These calculations were carried out for different intermolecular potentials. The values obtained using this theory are compared with the experimental results.