bluuebunny/crossref_metadata_2025 huggingface dataset:
Photochemical Studies by Means of a Field Ion Mass Spectrometer
Authors: Okabe H. , D. Beckey H. , Groth W.
Published: March 2015

A mass spectrometric investigation was carried out on the direct photolyses of propene, 1-butene, and hydrazine at 1849 A with a field ion source in a flow system. Comparisons were made with Pt tip and wire emitters. It was found that, without illumination, mass spectra obtained with the wire were accompanied by a number of fragment peaks amounting to almost 1%. Since these peaks interfere with those produced photochemically, the tip emitter was used mostly for the photochemical studies although it gave 100 times less current and was less stable. The photochemical products formed at a gas pressure of 10 μ by a low pressure mercury lamp were detected after approximately 10 m sec. The three main peaks observed in the propene photolysis were at masses 27, 28, and 56, indicating the processes:

C3H6+hv→C2H3+CH3, C3H6+hv→C2H4+CH2, CH2+C3H6→C4H8.

The photolysis of 1-butene gave four main peaks at masses 40, 41, 42, and 70, suggesting steps, C4H8+hv→C3H4+ (H+CH3) or CH4, C4H8+hv→C3H5+CH3, C4H8+hv→C3H6+CH2, CH2+C4H8C5H10.

The only peak found with the photolysis of hydrazine was at mass 17, indicating the step, N2H4+hv→NH3+NH.

The possibility of forming these products by secondary processes is discussed.
Über die Feldstärkeabhängigkeit der Winkelverteilung feldemittierter Elektronen und Ionen
Authors: Beckey H. D. , Dahmen J. , Knöppel H.
Published: March 2015

The angular distribution of atoms and molecules field ionized at Platinum tips is determined. First, with negative polarity of the tip the angular distribution of the field emitted electrons is measured in order to determine he radius of curvature and the shape of the tip, using calculations of DRECHSLER and HENKEL 2.

Then the angular distribution of field ionized Argon is measured at a tip temperature of about 400 °K. The curve agrees qualitatively with one derived from GOMER’s 6 equations on field ion currents as a function of field strength.

In contrast with this curve which shows a continuous decay with polar angle, the angular distribution curve of field ionized n-hexane, acetone, water and methanol shows a side-maximum lying at a polar angle of about 40°. This is explained as the consequence of adsorption and particle supply phenomena.
Overhauser-Effekt und Relaxation in organischen Festkörperradikalen
Authors: Haupt J. , Müller-Warmuth W.
Published: March 2015

The dynamic proton polarization, and the proton and electron spin relaxations have been studied in the organic polycrystalline free radicals bis-diphenylene-p-chlor-phenyl allyl (BPA), diphenyl picryl hydrazyl (DPPH), WURSTER'S blue perchlorate (WBP) and galvinoxyl (GAV). Enhancement factors between +370 and +79 were observed; extrapolation to infinite microwave power yielded values near the theoretical γs/γI ratio. Electron spin-lattice relaxation times are of the order of 10-7 to 10-8 sec; proton relaxation times are of the order of 10-3 sec. With the exception of galvinoxyl at low temperatures, the proton resonance line shapes are not much influenced by the local field of the unpaired electrons. The ESR spectra show a typical exchange-narrowing. All the results are discussed in terms of a scalar nuclear-electron interaction in which electron-electron exchange couplings provide a time dependence of random character.
Decomposition of NaCl-KCl Mixed Crystals
Authors: Graeffe G. , Nurmia M.
Published: March 2015

The decomposition of equimolar NaCl—KCl mixed crystals was studied at different temperatures with calorimetric and capacitance measurements. Comparison with other studies indicates that the decomposition proceeds in three steps. The main heat emission and change of the dielectric constant take place during the second step. The activation energies of the steps are nearly equal.
Kinetic Theory for a Dilute Gas of Particles with Spin
Authors: Hess S. , Waldmann L.
Published: March 2015

The kinetic theory of particles with spin previously developed for a LORENTzian gas is extended to the case of a pure gas. In part A the transport (BOLTZMANN) equation for the one particle distribution operator is stated and discussed (conservation laws, Η-theorem). A magnetic field acting on the magnetic moment of the particles is incorporated throughout. In part B the pertaining linearized collision operator and certain bracket expressions linked with this operator are considered. Part C deals with the expansion of the distribution operator and of the linearized transport equation with respect to a complete set of composite irreducible tensors built from the components of particle velocity and spin. Thus, the distribution operator is replaced by a set of tensors depending only on time and space-coordinates. The physical meaning of these tensors (expansion coefficients) is invoked. They obey a set of coupled first-order differential equations (transport-relaxation equations) . The reciprocity relations for the relaxation matrices are stated. Finally a detailed discussion of angular momentum conservation is given.
Extremaleigenschaft thermodynamischer Gleichgewichtszustände bei Ähnlichkeitstransformationen
Authors: Lenk Richard
Published: March 2015

Some inequalities are derived from the extremal properties of thermodynamic equilibrium states. Nonequilibrium states with the same volume and entropy as the equilibrium state are constructed by scale transformations from the equilibrium distributions to other values of volume and entropy.

A volume-changing scale transformation gives the virial theorem and a stability condition for any system. An entropy-changing scale transformation yields the equipartion theorem and the condition C ν Cν
id for classical systems. A combined scale transformation gives a new stability condition which is more stringent than the condition belonging to the virial theorem. The latter degenerates to an identity for ideal systems, the former for a classical plasma.
Stabilität von Vielteilchensystemen bei äußeren Störungen:
Authors: Lenk Richard
Published: March 2015

As a consequence of the Second Law of Thermodynamics the imaginary parts of linear response functions are positive definite for positive frequencies. Resulting from this fact inequalities based on the fluctuation dissipation theorem are derived for the moments of these imaginary parts and of the related correlation functions. Moments without physical meaning have been eliminated.
The Wannier Functions of the Lattice Electron in a Uniform Magnetic Field
Authors: Jannussis A.
Published: March 2015

In this paper a generalization of the WANNIER functions is performed for the case of the lattice electron moving in a uniform magnetic field.

In the case of the free electron moving in a uniform external magnetic field, the WANNIER function may be obtained directly by the Schrauben-function, if the wave vector k is substituted by the vector potential — (1/c) A (ai).
Nonlinear Coordinate Transformations for Vibrations of Simple Polyatomic Molecules, Using the Cihla-Pliva Formalism
Authors: Cyvin S. J.
Published: March 2015

Nonlinear coordinate transformations are considered for the molecular vibrations of the bent symmetrical XY2 and tetrahedral Z4 models. Algebraic expressions are given for internal coordinates as expanded through cubic terms, using a method due to CIHLA and PLÍVA. The method is compared to other approaches, viz. those of MORINO et al. on one hand, and PARISEAU et al. on the other. A conclusions is given in favour of the CIHLA-PLÍVA method as regard to a systematic treatment of polyatomic molecules. A similar conclusion applies also to the connected type of calculations where electronic computers are employed.
Gruppentheoretische Betrachtung zum Torsions-Rotations-Spektrum von Wasserstoffperoxyd
Authors: Dreizler H.
Published: March 2015

Es wird die Invarianzgruppe eines bekannten HAMILTON-Operators, der die Torsion und Rotation von H2O2 beschreibt, gegeben. Dabei erweist es sich als notwendig, den Basisbereich des Torsionswinkels η mit 4 π zu wählen. Mit dieser Gruppe wird eine Klassifizierung der Energieterme durchgeführt und Auswahlregeln abgeleitet.

Die Ergebnisse sollten auch für Strukturanaloge des Wasserstoffperoxyds anwendbar sein.
Rotationsspektren in angeregten Schwingungszuständen und Torsionspotential von Furfurol
Authors: Mönnig F. , Dreizler H. , Rudolph H. D.
Published: March 2015

Für beide rotationsisomere Formen des Furfurols werden Rotationsspektren in angeregten Zuständen der drei frequenzniedrigsten Schwingungen mitgeteilt. Durch Intensitätsvergleich mit Linien des Grundzustandes werden die Schwingungsfrequenzen bestimmt und mit Hilfe des Trägheitsdefekts die Schwingungsformen festgestellt. Die Ergebnisse werden mit dem Spektrum des Moleküls im fernen IR, das ebenfalls angegeben wird, verglichen. Aus den Torsionsfrequenzen und dem Energieunterschied zwischen beiden Formen ergibt sich ein Hinderungspotential

Für dieses Potential wurden die unteren Torsionsniveaus und -funktionen berechnet. — Außerdem wird auf einige Summenregeln für den Trägheitsdefekt aufmerksam gemacht.
Die Flügel der Balmer- und Paschen-Linien des atomaren Wasserstoffs: Ein Vergleich zwischen Theorie und Experiment
Authors: Pfennig Hans
Published: March 2015

The profiles of the BALMER- and PASCHEN-lines of hydrogen being emitted from a plasma of relatively low electron-density and temperature (Ne = 1.3 × 1013 cm-3, T=1 850 °K) are compared with theoretical profiles based on a quasistatic treatment of the ions and electrons. For a region extending from the line wing to a point lying well inside of HOLSTEIN’S frequency limit a satisfactory agreement with experiment can be achieved by using ECKER’S microfield-distribution folded with itself and by inserting values of the parameter r0/λ (r0≈mean particle distance, λ = DEBYE length) being roughly twice as high as one would calculate from the values of Ne and T. Within the framework of the quasi-static theory there seems to be no way of explaining the discrepancy between the high value of r0/λ which fits the experimental curves best and the theoretical value which is lower by a factor of about 2.
Die Elektronendichte im Z-Pinch als Funktion von Ort und Zeit
Authors: Böhnlein A.
Published: March 2015

An einer Z-Pinchanordnung (ƒ=100 kHz, W=3 kJ) mit einem Entladungsgefäß von 20 cm Durchmesser und 50 cm Höhe wird bei einem Fülldruck von 1 Torr H2 die Elektronendichte als Funktion von Ort und Zeit aus der photoelektrisch gemessenen Strahlungsintensität des PAscHEN-Kontinuums bei 5500 A bestimmt. Aus der „side on“ beobachteten Intensität wird unter Berücksichtigung der Absorption im Säulenkern zunächst die radiale Verteilung des Emissionskoeffizienten berechnet. Durch Vergleich mit dem theoretischen Emissionskoeffizienten, der nach KRAMERS und UNSÖLD proportional zum Quadrat der Elektronendichte ist und im allgemeinen nur schwach von der Temperatur abhängt, ergibt sich dann die Elektronendichte. Die in das Auswerteverfahren nur schwach eingehende Temperatur wird aus den ebenfalls gemessenen spektralen Intensitätsverteilungen für verschiedene Orte über den Entladungsquerschnitt im Wellenlängenbereich von 5200 bis 7000 A abgeschätzt.
Der Anstieg des Tritiumgehaltes im atmosphärischen Wasserstoff seit 1960
Authors: Ehhalt D. , Roether W. , Stich W.
Published: March 2015

Measurements of the tritium and deuterium content of atmospheric hydrogen are reported. The measured tritium is corrected for local contamination by industrial hydrogen. The samples cover the period from 1960 to 1965. The tritium content shows a marked increase in 1961 but rises only slowly during 1962 and 1963. There is evidence for a further increase in the tritium content starting in fall 1964. The explanation suggested is, that tritiated hydrogen is injected into the high stratosphere by thermonuclear explosions and mixed down into the troposphere with a 2—3 years delay. Thus one would ascribe the first increase to 1958 testing, the second to the 1961/1962 thermonuclear test series.
Note on Data Analysis for Streamer Track Chambers
Authors: Fries D. E. C.
Published: March 2015

The analysis of streamer track chamber data can be performed using parts of the available bubble chamber analysis procedures with the exception of the geometrical part. Here major modifications are required in order to fit particle tracks to unmeasured vertices and to account for nonuniform magnetic fields. A method and its test, which is suited to handle these particular problems, is described.
VB + CI-Berechnungen an den Hydriden NH und OH
Authors: Grün N.
Published: March 2015

Die Grundzustände der Hydride NH und OH werden mit verschieden ausführlichen Sätzen von Versuchsfunktionen berechnet. Der Abfallparameter der 1s-Funktion vom Wasserstoffatom wird variiert. Ionenstrukturen N-H+ und O-H+ werden berücksichtigt und dabei für N- und O- auch Konfigurationen p3p′ bzw. p4p′ mit einem „weiter außen“ eingebauten p′-Elektron verwendet. Für die Grundzustände werden Dipolmomente berechnet. Angeregte Terme werden mit einem kleinen Satz von Funktionen behandelt. Zu den Grundzuständen und den angeregten Zuständen werden Potentialkurven gezeichnet und daraus mit Hilfe eines Polynoms vierten Grades spektroskopische Daten gewonnen.
Zur Temperaturabhängigkeit der Felddissoziation von Molekülionen
Authors: Knöppel H. , Beckey H. D.
Published: March 2015

The temperature dependence of field dissociation of organic molecular ions as described in this paper can be interpreted qualitatively by means of simple models.

Very fast decomposition processes, occurring about 10-12 sec after field ionization, are not only due to the lowering of the dissociation energy by the field, but also due to fluctuation of vibrational energy, especially at higher temperatures.

The fragment ion insensities are increased by formation of adsorbed layers on the tip anode at low temperatures, especially with substances having high dipole moments.

In the case of molecules containing a polar group and an alkyl chain, only the former is ordered preferrentially, with the dipole moment parallel to the field lines, whereas the latter is relatively mobile in the electric field.

The relative fragment ion intensities depend on the orientation of the alkyl chain relatively to the polar group, however, this effect does not depend appreciably on temperature because of the mobility of the alkyl chain. The only exception from this rule was observed with pentanol. The pentanol molecules are adsorbed at the tip anode with the alkyl chains preferrentially parallel to each other. This leads to a preferred formation of C2H5
+ fragment ions. With increasing temperature, the adsorbed layer is removed and a statistical orientation of the alkyl chain becomes more important, thus reducing the relative C2H5
+ abundance.
On Minimum-B Stabilization of Electrostatic Drift Instabilities
Authors: Saison R. , Wimmel H. K.
Published: March 2015

A check is made of a stabilization theorem of ROSENBLUTH and KRALL (Phys. Fluids 8, 1004 [1965]) according to which an inhomogeneous plasma in a minimum-B field (β ≪ 1) should be stable with respect to electrostatic drift instabilities when the particle distribution functions satisfy a condition given by TAYLOR, i. e. when f0 = f(W, μ) and ∂f/∂W < 0 Although the dispersion relation of ROSENBLUTH and KRALL is confirmed to first order in the gyroradii and in ε ≡ d ln B/dx z the stabilization theorem is refuted, as also is the validity of the stability criterion used by ROSEN-BLUTH and KRALL, ⟨j·E⟩ ≧ 0 for all real ω. In the case ωpi ≫ | Ωi | equilibria are given which satisfy the condition of TAYLOR and are nevertheless unstable. For instability it is necessary to have a non-monotonic ν ⊥ distribution; the instabilities involved are thus loss-cone unstable drift waves. In the spatially homogeneous limiting case the instability persists as a pure loss cone instability with Re[ω] =0. A necessary and sufficient condition for stability is D (ω =∞, k,…) ≦ k2 for all k, the dispersion relation being written in the form D (ω, k, K,...) = k2+K2. In the case ωpi ≪ | Ωi | adherence to the condition given by TAYLOR guarantees stability.
Rankine–Hugoniot-Berechnungen für Nichtgleichgewichts-Plasmen
Authors: Artmann J.
Published: March 2015

In optically thin plasmas produced by strong shock waves the SAHA equation is no longer valid to describe the conditions directly behind the shock wave. Photoionisation may be neglected in the balance of production and recombination of charged particles. For the case of nonequilibrium a calculation assuming various ratios of electron to ion temperature (ϑ= TeT) shows that the shock wave parameters are described sufficiently well by the Korona-equation. Temperature, density ratio and electron density are increased with increasing ϑ whereas the pressure ratio is independent of the kind of equilibrium and ϑ.
Massen-Geschwindigkeitsfilter für künstlich beschleunigten Staub
Authors: Rudolph V.
Published: March 2015

Zur Massen-Geschwindigkeitsseparation von geladenem, künstlich beschleunigtem Staub wurde ein elektrostatisches Filtersystem entwickelt und erprobt. Der logische Teil dieses Filters kann auch zur Messung der Ladung und Geschwindigkeit von kosmischem Staub dienen.
Eine VB-CI-Beredinung des Ammoniakmoleküls
Authors: Moraw Helmut
Published: March 2015

In dieser Arbeit wird eine Berechnung des Ammoniakmoleküls mit der Valenzstrukturmethode unter gleichzeitiger Berücksichtigung von Konfigurationswechselwirkung (VB-CI-Methode) und Hybridisierung der Einelektronenfunktionen der L-Schale des N-Atoms durchgeführt. Als Einelektronenfunktionen werden „SLATER-Orbitals“ verwendet. Die benutzten Abschirmkonstanten und die beiden Kernabstände werden durch eine grobe Variation optimalisiert. Mit einem Satz von 12 Funktionen für den Grundzustand des Moleküls, der durch eine symmetrische Singulettfunktion (1A-Funktion) charakterisiert ist, wird eine Näherung der Potentialkurve für das Durchschwingen des N-Atoms durch die Ebene der Η-Atome berechnet. Die so erhaltene Höhe des Potentialwalls ist etwa um einen Faktor 3 zu groß, so daß sich eine Berechnung der Inversionsaufspaltung nicht durchführen läßt. Für die optimale Zustandsfunktion ergibt sich ein Energiewert von —56,0565 DRY, was einer Bindungsenergie von 62,7% des experimentellen Wertes entspricht. Die Kernabstände NH und HH ergeben sich zu 2,0415 a. E. bzw. 3,085 a. E., d. h. um 6,5% bzw 0,3% größer als die experimentellen Werte. Außerdem wird das Dipolmoment des Moleküls in Abhängigkeit von der Pyramidenhöhe und für die optimalen Abschirmkonstanten und Kernabstände in Abhängigkeit vom Hybridisierungswinkel berechnet. Beim für die Energieberechnung optimalen Winkel ergibt sich ein Dipolmoment von 0,755 a. E., das um etwa 30% höher als der experimentelle Wert von 0,574 a. E. ist. Weiterhin werden Elektronendichten in zwei Ebenen des Moleküls berechnet und in Form von Linien gleicher Dichte graphisch dargestellt. Schließlich werden noch einige angeregte Zustände des Moleküls berechnet.
Die kinetische Energie ionisierter Molekülfragmente
Authors: Fuchs R.
Published: March 2015

It is well known that in the initial energy spectra of hydrocarbon fragment ions formed by electron impact, satellite ion groups occur which are believed to be mainly due to the fragmentation of doubly charged ions into two singly charged fragments. By using an electron energy of 150 eV a new type of satellite was observed in the initial energy spectra of C1Hk
+ and C2Hl+ fragment ions from hydrocarbons with three and more carbon atoms. The n-paraffins were investigated systematically up to n-decane. Because the initial energy of these satellites is nearly twice the initial energy of the already well known “first” satellites, it is suggested that these newly discovered “second” satellites are due to an analogous fragmentation process of the type

A+++→B+ + C++.

Therefore, a careful search was made for the corresponding doubly charged fragment ions of high kinetic energy. Well pronounced satellite groups of doubly charged fragment ions were, indeed, found. Their momentum approximately equals the momentum of the corresponding “second” satellites of singly charged fragments, which supports the suggested mechanism.
Kinetic Energy Release in Metastable Transitions. I
Authors: Barber M. , R. Jennings K. , Rhodes R.
Published: March 2015

A method is described for detecting metastable transitions which take place with the release of kinetic energy in the field-free region between the source and electrostatic analyser of a doublefocusing mass spectrometer, and a procedure is given for evaluating the kinetic energy release. Values are given for a number of transitions and are in agreement with those obtained by other methods where comparison is possible. The variation of peak shape with accelerating voltage is ascribed to the varying efficiency with which product ions are collected.
Absolute Präzisionsbestimmung von Gitterkonstanten an Germanium- und Aluminium-Einkristallen mit Elektroneninterferenzen
Authors: Witt W.
Published: March 2015

An absolute precision determination of lattice constants by electron diffraction is made with thin monocrystalline films of germanium and aluminium, having a thickness between 1000 and 5000 A. The films are prepared from the bulk material by mechanical polishing and subsequent chemical polishing or etching. The obtained values for the lattice constant α of both materials are within the accuracy Δα/α= ±3·10-5 of measurement in full agreement with the corresponding values obtained by X-ray diffraction (Smakula and Kalnajs).
Semi-empirical Molecular Orbital Energy Levels of the Hexammine and Chloroammine Complexes of Co(IV)
Authors: Yeranos Walter A. , Hasman David A.
Published: March 2015

Using the recently proposed reciprocal mean for the semi-empirical evaluation of resonance integrals, as well as approximate SCF wave functions for Co3+, the one-electron molecular energy levels of Co (NH3) 3+, Co (NH3) 5Cl2+, and Co (NH3) 4Cl2
1+ have been redetermined within the WOLFSBERG–HELMHOLZ approximation. The outcome of the study fits remarkably well with the observed electronic transitions in the u.v. spectra of these complexes and prompts different band assignments than previously suggested.
Die Umordnung der Bindungselektronen in den Anionen durch das Proton, eine IR-spektroskopische Untersuchung von Polyelektrolyten
Authors: Zundel G.
Published: March 2015

5 μ thick polyelectrolyte films were IR-spectroscopically investigated at different degrees of hydration. In the salts essentially equal XO-bonds, i. e. very high mesomerism, are found in the anions. When however the proton approaches the anion, it rearranges the bonding electrons. Bonds with single- and double-bond character are observed. The mesomerism is highly decreased. The bands of the stretching vibrations of the bonds of these anions can hence serve as a measure of the degree of true dissociation. The latter shows a characteristic progression; it decreases in passing from polystyrene sulphonic acid to polystyrene phosphorous acid. This progression is closely connected with the observed mesomerism in the anions.
Self-Diffusion and Transport Mechanisms in Cubic Lithium Sulphate
Authors: Kvist Arnold , Trolle Ulf
Published: March 2015

The self-diffusion coefficient of the lithium ion in cubic lithium sulphate has been measured from 640 to 790°C. From electrical conductivity and electromigration experiments it has been found that several cations are moving in phase and the mean value of the number of ions in each group has been estimated to be about 2.0. The measurements of the self-diffusion coefficient indicate that we also have transport mechanisms, which contribute more to the diffusion than to the electrical conduction.
Ethylene Wave Functions in the S.C.F. Approximation
Authors: Rajagopal P.
Published: March 2015

S.C.F. Calculations on eight planar configurations of ethylene are reported.
Zur Ultrarot-Dispersion zweiachsiger und einachsiger Kristalle I
Authors: Merten L.
Published: March 2015

Die Kopplung der optischen Gitterschwingungen (unter Berücksichtigung ihrer Dämpfung) mit den elektromagnetischen Lichtwellen läßt sich für doppelbrechende kristallographisch zweiachsige und einachsige Kristalle ähnlich wie für kubische Kristalle vollständig im Rahmen einer phänomenologischen Theorie beschreiben. Es ergibt sich eine Dispersionsformel, die auf die äußere Form der FRESNELSchen Normalengleichung gebracht werden kann, in der die dielektrischen Konstanten durch dielektrische Resonanzglieder (LORENTZ-Terme) ersetzt sind. Aus der Dispersionsgleichung erhält man insbesondere die Richtungsabhängigkeit der optischen Konstanten (Brechungsindex n, Absorptionskoeffizient k) und damit der optischen Spektren im Reststrahlgebiet.

Für n→∞ (k=0) ergeben sich die reinen Gitterschwingungen. Ihre Frequenzen gehorchen gewissen Summations- und Produktregeln.
Zum Thermotransport in Wolfram
Authors: Neumann G.M.
Published: March 2015

Aus der an hochgeglühten Wolframdrähten im elektrischen Potentialgradienten und im Temperaturgradienten auftretenden Oberflächenstrukturierung ergibt sich im Zusammenhang mit der elektrischen Überführung von Wolfram zur Kathode ein Thermotransport von Wolfram zum kälteren Probenteil. Die Transportwärme wird an Hand der Stufenstruktur sowie aus theoretischen Daten abgeschätzt.
IR-Untersuchungen heterocyclischer Verbindungen
Authors: Joeckle R. , Lemperle E. , Mecke R.
Published: March 2015

Die CH-Intensitäten heterocyclischer Fünfringe sind bedeutend kleiner als die der entsprechenden homocyclischen Verbindungen. Die Intensitäten nehmen bei den einfachen Fünfringen (C4H4X) in der Reihenfolge X=S, NH, O ab, bei deren Benzologen (C8H6X und C12H8X) in der Reihenfolge NH, S, O. Die Intensitätsabnahme ist von einer Verschiebung des Bandenschwerpunktes der CH-Valenzschwingungen ins Kurzwellige begleitet. Durch Einbau weiterer Hetero-N-Atome in den Ring werden die Effekte auf ICH und v̅CH verstärkt. Es wurde versucht, die beobachteten Resultate sowohl durch Änderung des Hybridisierungsverhältnisses in den CH-Orbitalen als auch durch die unterschiedliche Elektronen-Saugwirkung der Heteroatome und die damit verbundene geänderte Ladungsverteilung im Molekül qualitativ zu erklären.
Theory of Electron Diffraction by Crystals
Authors: Kambe Kyozaburo
Published: March 2015

A general theory of electron diffraction by crystals is developed. The crystals are assumed to be infinitely extended in two dimensions and finite in the third dimension. For the scattering problem by this structure two-dimensionally expanded forms of GREEN’S function and integral equation are at first derived, and combined in single three-dimensional forms. EWALD’S method is applied to sum up the series for GREEN’S function.
Experimentelle und theoretische Untersuchungen zum plastischen Verhalten kubisch-flächenzentrierter Vielkristalle
Authors: Schwink Ch. , Vorbrugg W.
Published: March 2015

Für die Bereiche 1 und 2 der in früheren Untersuchungen 9-11 gewonnenen Einteilung der Verfestigungskurve kubisch-flächenzentrierter Vielkristalle, die bis zum Beginn dynamischer Erholungsvorgänge (Quergleitung) reichen, wird eine Versetzungstheorie entwickelt und experimentell geprüft. Sie führt die Spannungs-Dehnungskurve quantitativ auf den mittleren Laufweg der die Verfestigung verursachenden Versetzungen zurück. Unsere Einzelergebnisse sind:

1. Für Bereich 1 wird zur Berechnung des Versetzungslaufwegs eine geeignete Definition des mittleren Korndurchmessers gegeben und gezeigt, wie sich dessen Zahlenwert aus Schliffbildern ermitteln läßt.

2. Das Gleitlinienbild wird an Nickelproben für eine tiefe (85°K) und eine höhere (295°K) Verformungstemperatur elektronenmikroskopisch studiert, Gleitliniendichte und Mehrfachgleitung werden quantitativ erfaßt. Die mittlere Gleitlinienlänge als Funktion der Spannung σ erweist sich als eine charakteristische, doppelt gekrümmte Kurve.

3. Die Verfestigung in Bereich 1 läßt sich theoretisch beschreiben, wenn man für den verfestigungsbestimmenden Versetzungslaufweg den oben definierten mittleren Korndurchmesser wählt und außerdem berücksichtigt, daß dieser mit zunehmender Spannung σ langsam abnimmt.

4. In Bereich 2 wird die Verfestigung durch den infolge von Versetzungsreaktionen im Korninneren abnehmenden Versetzungslaufweg bestimmt. Er stimmt hier mit der mittleren Gleitlinienlänge überein. Die aus den Gleitlinienmessungen mit unserer Theorie gefolgerten Verfestigungsparameter stimmen mit den unmittelbar gemessenen sehr gut überein.

5. Physikalische Überlegungen und der Vergleich mit den Experimenten legen es nahe, daß der sogen, mittlere Orientierungsfaktor in Bereich 1 Werte um 2,7, in Bereich 2 dagegen Werte um 2.3. nahe dem Sachs sehen Wert, annimmt.
Negative Ionen durch Elektronenstoß aus organischen Nitroverbindungen, Äthylnitrit und Äthylnitrat
Authors: Jäger K. , Henglein A.
Published: March 2015

Negative ion formation by electron impact has been studied in nitromethane, nitroethane, nitrobenzene, tetranitromethane, ethylnitrite and ethylnitrate. Appearance potentials, ionization efficiency curves and kinetic energies of negative ions were measured by using a Fox ion source. The electron affinities of C2H5O and of C (NO2)3 are discussed as well as the energetics of processes which yield NO2
-. The electron capture in nitrobenzene and tetranitromethane leads to molecular ions [C6H5NO2~ in high, C (NO2)4 in very low intensity] besides many fragment ions. A number of product ions from negative ion-molecule reactions has also been found.
UR- und UV-spektroskopische Untersuchungen einiger Azomethine
Authors: Krauss Walther , Wagner Claus G. J.
Published: March 2015

Die Lage und die integrale Intensität der UR-(C=N)-Valenzschwingung parasubstituierter Benzalaniline in verschiedenen Lösungsmitteln werden untersucht. Die verwendeten Lösungsmittel üben keinen signifikanten Einfluß auf beide Größen aus. Die HAMMETTSchen σ-Konstanten können Abschätzungen über Substituenteneffekte auf die Intensität und umgekehrt erlauben.

Bei Konjugation der (C=N) · zu einer (C=C)-Bindung tritt eine Bandenaufspaltung auf. Es wird versucht, dies durch eine symmetrtische und antisymmetrische Valenzschwingung des Gerüstes zu interpretieren.

Die UV-Spektren der Azomethine und einiger Komplexe werden vermessen, wobei als Intensitätsmaß die Oszillatorenstärke dient. Auf Grund der UR- und UV-Messungen wird der Versuch unternommen, die Bandendaten durch ein System zu deuten, bei dem der Kettenstickstoff als Begrenzung angenommen wird. Zum Vergleich werden entsprechende Aldehyde herangezogen. Der Annahme eines starken Herausdrehens des Anilinringes aus der Gerüstebene können wir uns nicht ohne weiteres anschließen.
Edelgasmessungen an Eisenmeteoriten
Authors: Schultz L. , Hintenberger H.
Published: March 2015

The spallogenic isotopes of helium, neon, and argon have been measured in 36 iron meteorites using a statically operated double focusing mass spectrometer. The following relations were found between the concentration ratios of the cosmic ray produced isotopes 3He, 4He, 21Ne, and 38Ar:

3He/4He = (36.0 ± 0.9) 21Ne/4He+ (0.148 ± 0.015),

38Ar/21Ne= (9.4±0.8) x 10-3
4He/21Ne+ (2.06±0.04).

From the 38 Ar/21Ne ratio a parameter n was calculated for each sample which according to GEISS, OESCHGER und SCHWARZ is a number measuring the effective irradiation hardness. Relations between n, 3He/4He, 3He/21Ne, and 4He/21Ne have been studied.

A slight variation of the 36Ar/38Ar has been found which is correlated to the effective irradiation hardness. The spallation yield of 36Ar relative to the total isobaric yield does not depend on the effective irradiation hardness.
Anisotrope Kernresonanzfluoreszenzausbeute von Cr-Atomen in einem Vanadiumeinkristall
Authors: Kalus J. , Neuhauser J. , Puckert E.
Published: March 2015

Die bereits früher für einige Kristallrichtungen nachgewiesene Anisotropie der Kernresonanzfluoreszenz 1 am 1,43 MeV-Niveau von Cr52 an neutronenbestrahlten V51-Einkristallen, die infolge der anisotropen Abbremsung der Cr-Atome (Anfangsenergie 20—90 eV) auftritt, wurde bei Drehung des Kristalles um die 〈110〉-Achse in 10°-Intervallen gemessen. Der Anisotropieeffekt beträgt bis zu 10%. Es zeigt sich, daß ein Hartkugelmodell mit sprungartiger Abbremsung nach dem ersten Stoß mit einem Nachbaratom zur Deutung der Messungen nicht ausreicht. Dagegen liefert ein realistischeres Modell mit Mehr-Stufen-Abbremsung gute Übereinstimmung mit den Messungen.
Überlegungen zum verallgemeinerten Heisenberg—Diracschen Austauschoperator (Anwendung auf Nickel)
Authors: Lindner U. , Gruner R. , Heber G.
Published: March 2015

By comparing theory and experiment we try to find out, if the effective Spin-Hamiltonian (2) is applicable for a metal like Nickel. We get no contradictions.
Die Hochfrequenz-Resonanz-Sonde
Authors: Peter Günter
Published: March 2015

Dc and ac currents to a rf resonance probe were investigated experimentally in the frequency range from 1 to 100 Mc/s in a quiescent Cesium plasma. The measurements in the plasma are explained by calculations and measurements with a lumped-constant equivalent network (“plasma simulator”).

It is shown that the ac current to the probe is strongly influenced by the capacitance of the cable leading to the probe. A device to compensate this cable-capacitance is developed and used. Furthermore, it is shown for the first time that the double (or devided) main resonance maximum, occurring frequently with dc and ac currents to the resonance probe, is generally due to the influence of a second reference electrode.

A simple and direct (“focus”) method for very precise plasma density determination (from the intersection point of the rf-current-vs.-frequency curves with probe voltage as parameter) is developed and compared with ac transmission current and LANGMUIR probe measurements at plasma densities between 2 × 106 and 3 × 107 cm–3. Agreement is obtained between these three experimental methods within their margins of error. The comparison leads to a better understanding of the measured LANGMUIR characteristic and of the Cs-plasma of the “Alma I” device.
Selbstaktivierte Lumineszenz, Photoleitung und Donatoren in ZnS-Einkristallen
Authors: Siebert Dieter , Teitge Heinrich
Published: March 2015

The temperature dependence of the photoconductivity and the luminescence of ZnS-single crystals containing Α-centers were investigated. The results are discussed using the model first suggested by PRENER and WILLIAMS.
γ-Radiolyse von flüssigem Kohlenoxid bei —196°C
Authors: Buschmann H. W. , Groth W.
Published: March 2015

The radiation chemistry of liquid carbon monoxide at —196°C and mixtures of CO with various gases has been investigated. In the γ-radiolysis of pure CO CO2 is formed with G(CO2) =0.18. The addition of CH4, C2H4, O2, and NO leads to the formation of C3O2 which is not observed in the γ-radiolysis of pure CO.

In the case of CO—CH4 mixtures the following reacting products were identified: C2H6, C2H2, H2CO, H2C2O (Ketene), CO2 and C3O2. Results of experiments with CO —CH4
—13CH4 and CO—CH4—CD4 mixtures and measurements of the dependence of G(CO2), G(C3O2), G(C2H2) and G (C2H6) on the concentration of CH4 have shown that ethane is formed by energy transfer from CO to CH4 or by reaction of CH4 with excited CO and that C3O2 and C2H2 are formed by reaction of free carbon atoms which are formed in the presence of methane.
Chemische Reaktionen des O--Ions im Massenspektrometer
Authors: Jäger K. , Simic M. , Henglein A.
Published: March 2015

Fast reactions of 0- with water, various alcohols, diethylether, acetone, c-hexane, c-hexene, benzene and toluene have been observed. The following types of reactions which often compete in these systems have been found: a) Η-atom transfer (such as CH3OD+O- → OH-+CH2+CH2OD), b) Proton (deuteron) transfer (such as CH3OH+O-→ CH3O–+OH, and CH3OD+O-→ CH3O-+OD), c) H2
+-transfer [such as (CH33)2CO+O- → C3H4O-+H2O], d) dissociative proton transfer (such as i-C3H7OH+O- → C2H3O-+OH+CH4 or C3H5O-+OH+H2), e) dissociative addition (such as C6H6 → C6H5O-+H).
Zur Theorie der Supraleitung in planparallelen Schichten geringer Dicke
Authors: Raufuss Henning
Published: March 2015

The GORKOV equations are solved for ideal planar films of superconductors. For the purpose of comparison, two different formulations of the self-consistency condition are used; the first is characterised by a cut-off factor in the energy integral, the second by the termination of the ω summation at the same cut-off value. Certain values of the film thickness (those corresponding to resonance intervalls in the sense of THOMPSON and BLATT) are excluded, but they are not decisive to this treatment. By this means, a fairly accurate check of the error in the approximation is made possible. This allows a quantitative comparison of the critical temperatures and of the two forms of the gap function calculated from the two formulations of the basic equations.

At absolute zero, both formulations of the theory become equivalent and lead to essentially identical relations between the gap function and film thickness. However, the critical temperature which results from the termination of the ω summation is noticeably higher than that calculated with the help of the energy cut-off.
Feldemission aus In2S3
Authors: Neumann H.
Published: March 2015

Die Abhängigkeit des Feldelektronenstroms von Belichtung und Temperatur wurde für In2S3-Kristalle mit unterschiedlichem spezifischem Widerstand untersucht. Die Strom-Spannungs-Kennlinien niederohmiger Kristalle werden durch Änderung von Belichtung und Temperatur nicht beeinflußt. Hochohmige Kristalle zeigen beträchtliche Nichtlinearitäten im Kennlinienverlauf, die sich durch Spannungsabfall am Emitter und durch Ladungsträgervervielfachung erklären lassen. Die experimentellen Daten deuten auf Emission aus einem an der Oberfläche entarteten Leitungsband hin. Die gefundenen negativen Feldemissionskennlinien können durch induzierten Stoßionisationsdurchschalag von mit Elektronen besetzten Haftstellen verursacht sein.
Über den Einfluß der Adsorption auf die Feldionisierung organischer Substanzen
Authors: G. Metzinger H. , Beckey H. D.
Published: March 2015

A new effect was observed: The overall field ion current generated by thin wires or tips changes with the average work function of the metal if different organic substances are adsorbed.

The shift of the tunneling probability versus voltage curve with change of work function and of ionization potential for molecules such as heptane, and heptene is calculated.

This is compared with the shift of the experimental current-voltage curves with change of work function and ionization potential when supplying different organic compounds into the field ionization chamber and after addition of small amounts of another organic substance to the substance under discussion.

Physically adsorbed substances on platinum, like n-paraffins, are always shifting these curves to higher voltages. This corresponds to a lowering of the average work function. The shift is more pronounced with alcohols on platinum because of the large work function change due to the polar groups. The higher aliphatic alcohols — starting with pentanol — are forming two dimensional condensed phases as postulated by KEMBALL. This was proven by detection of stepwise increase of dimeric ions in the FI mass spectra of pentanol as compared with the lower alcohols. The hydrocarbon chains of the alcohol molecules are ordered perpendicular to the metal surface in these phases.

Benzene, ethylene and acetylene additives are shifting the FI-curves of paraffins to lower voltages, thus indicating a chemisorption process of these unsaturated compounds increasing the average work function of the platinum surface.
Investigation of a Caesium Plasma Diode Using an Electron Beam Probing Technique 1, 2
Authors: Ott Werner
Published: March 2015

The plasma in a plane caesium diode with a hot emitter and a cold collector was investigated experimentally with a ribbon-shaped electron beam. The ribbon beam is projected through the diode at an angle of 45 degrees to its axis and allowed to strike a fluorescent screen. Variations in the axial electric field of the diode cause the ribbon beam to be distorted. The image of the distorted beam as seen on the fluorescent screen then constitutes a plot of the axial electric field along the axis of the diode.

The field plots so obtained are compared with a theory in which the collisions of the charge carriers are neglected. By means of this comparison it is possible to evaluate the neutralization parameter, the plasma density, and an average drift energy of the charge carriers.

The results show that the theory correctly describes the different modes of the potential distribution and especially the transitions between modes of operation as long as the diode is free of oscillations.

The stability of the different possible static potential distributions was also investigated. It was found experimentally that the system is unstable if the electron emission is less than the ion emission and the collector potential is positive.
Polarisationsgradspektren mehrkerniger Aromaten: Tetracen, 3.4-Benztetraphen, 1.2, 3.4-Dibenzanthracen, 1.2, 5.6-Dibenzanthracen, Picen, Pentaphen
Authors: Kiessling Reiner , Hohlneicher Georg , Dörr Friedrich
Published: March 2015

Absorption, luminescence and polarization spectra of tetracene and five five-ringed catacondensed aromatics have been analysed. The relative polarization of vibronic transitions is given for molecules of symmetric D2h and C2v. A new electronic transition, not detectable in the absorption spectra, has been found in all five-membered compounds, lying between 30 000 and 42 000 cm-1. The vibrational pattern of the α-band is determined by at least two series of vibrations.
Untersuchungen zum Problem des An- und Abklingens der Lumineszenz organischer Molekülkristalle
Authors: Kramer K.
Published: March 2015

The theoretical background of the time behaviour of the luminescence of organic molecular crystals is shortly discussed and a measuring equipment is described to measure the rise and the decay of luminescence intensities over four decades. Results on single crystals of anthracene, pyrene, 2,3-dimethylnaphthalene and mixed crystals at 77°K and 300°K are reported and conclusions are drawn regarding the luminescence mechanism in mixed crystals. In an appendix, some methods of measuring luminescence decay times are compared.
Die Abklingdauer der Fluoreszenz von Naphthalin-Kristallen
Authors: El-Kareh T. B. , Wolf H. C.
Published: March 2015

The fluorescence decay time of naphthalene crystals has been measured as a function of sample thickness (1 μ-1 cm) and temperature (4.2°K-300°K) when excited in the first electronic state with UV pulses of short duration. A simple model is proposed to explain the decay mechanism, assuming constant quantum yield and oscillator strength and taking into account both Davydov-levels A and B. The reabsorption is found to be directly proportional to the temperature. The decay time of the lower Davydov-component can be measured directly as τA = (115 ± 5) nsec. The decay time of the higher level B is calculated from the dependence on the thickness as τB = (20 ± 10) nsec, and from the temperature dependence as TB= (30 ± 10) nsec.
Non-Equilibrium Thermodynamics of Boundary Conditions
Authors: Waldmann L.
Published: March 2015

In part I a well-known pair of cross phenomena, thermo-osmosis and mechano-caloric effect, in a dense gas is treated by a “thermo-hydrodynamical” method: the FOURIER and NAVIER-STOKES equations are adopted for heat conduction and viscous motion whereas in the boundary conditions MAXWELL’S thermal slip (3.1) and a mechanical surface heat flow (3.7) appear. Both of them are connected by an ONSAGER relation (3.9). So far, the underlying geometry was a special one (circular cylindrical capillary). In part II the boundary conditions problem at the interface between two immiscible fluids is considered in the general case, by the method of continuum non-equilibrium thermodynamics. The fluids are in viscous motion and conducting heat, such that total mass, momentum, angular momentum and energy are conserved. It is assumed that none of these quantities is concentrated in the interface (vanishing densities per unit area). This leads to the global conditions (6.3) for the forces and (6.8) for the normal energy flows at the interface. After the general expression (7.8) for interfacial entropy production is at hand, the global conditions are replaced by stronger local ones in the vein of thermo-hydrodynamics. Two possibilities are considered in this context: the interface a) does not and b) does carry two-dimensional flows of momentum and energy. In case a) the ensuing local boundary conditions are merely mechanical slip for the velocity fields and temperature jump for the temperature fields. In addition to these, in case b) a pair of cross effects naturally comes out, namely thermal slip and mechanical surface heat flow, and a thermal surface heat flow as well. This reassures the results of part I which had been obtained in a somewhat indirect way.
Isometry Groups with Surface-Orthogonal Trajectories
Authors: Schmidt Bernd
Published: March 2015

It is shown that the trajectories of an isometry group admit orthogonal surfaces if the sub-group of stability leaves no vector in the tangent space of the trajectories fixed. A necessary and sufficient condition is given that the trajectories of an Abelian group admit orthogonal surfaces.

In spacetimes which admit an Abelian G2 of isometries, the trajectories admit orthogonal 2-surfaces if a timelike congruence exists with the following properties: the curves lie in the trajectories and are invariant under G2; ωα and üα are linearly independent and orthogonal to the trajectories.
Refractive Index Measurements of Molten Salts with Wave-Front-Shearing Interferometry
Authors: Wendelöv Lennart W. , Gustafsson Silas E. , Halling Nils-Olov , Kjellander Rolf A. E.
Published: March 2015

A wave-front-shearing interferometer has been used to determine the refractive index of the alkali nitrates LiNO3, NaNO3, KNO3, RbNO3, and CsNO3 from the melting point to a temperature just below the decomposition point. The accuracy of these measurements has been estimated to ±3·10-5 which should be compared with ±3·10–3, being the estimated error in earlier determinations. The refractive index is found to depend almost linearly on temperature. For most of the investigated liquids, however, one gets a better fit to the measured values if a second order dependence is assumed.
Energetic Plasmas Produced by Laser Light on Solid Targets
Authors: Opower H. , Kaiser W. , Puell H. , Heinicke W.
Published: March 2015

Using two parallel simultaneously operating giant pulse lasers light intensities of 3 x 1012 W/cm2 were achieved in the focus on a LiD target. Ion energies in the expanding plasma stream of 4.5 keV were observed. Investigations on thin LiH targets showed, that the light pulse interacts only with a target layer several 10-4 cm in thickness. The magnitude of the ion flux is estimated and compared with experimental observations.
Mikrowellenspektrum, Struktur und Dipolmoment von Trichiorsilan und Methyltrichlorsilan
Authors: Mitzlaff M. , Holm R. , Hartmann H.
Published: March 2015

The rotational spectrum of several isotopic species of HSiCl3 and CH3SiCl3 was studied in the region from 8 to 40 Gc. From the derived rotational constants the following structural parameters were obtained using KRAITCHMAN'S equations:

dSi-H= (1.4655±0.0002) A, dSi-Cl= (2.0118±0.0009) A, ∢ Cl—Si—Cl= (110,60±0.25)°.

Furthermore the constants for centrifugal distortion DJ= (1.2 ± 0.4) kc for HSiCl3 and DJ= (0.19 ± 0.04) kc for CH3SiCl3, for the quadrupole coupling e Q Vzz= + 12.8 Mc and the dipole moment μ= (0.86 ± 0.01) D for HSiCl3 and μ= (1.91 ± 0.01) D for CH3SiCl3 were determined. The interaction of the overall-rotation with the internal rotation is discussed for CH3SiCl3, and the hindering barrier is estimated to be less than 200 cm-1.