bluuebunny/crossref_metadata_2025 huggingface dataset:
Verallgemeinerte Boltzmann-Gleichung für mehratomige Gase
Authors: Hess S.
Published: March 2015

A generalized quantum mechanical Boltzmann equation is derived for the one particle distribution operator of a dilute gas consisting of molecules with arbitrary internal degrees of freedom. The effect of an external, time-independent potential on the scattering process is taken into account. The collision term of the transport equation contains the two-particle scattering operator T and its adjoint in a bilinear way and is non-local. The conservation equations for number of particles, energy, momentum and angular momentum as well as the H-theorem are deduced from the transport equation. One obtains the correct equilibrium distribution operator even in the presence of an external field (e. g. for particles with spin in a homogeneous magnetic field). Some special cases of the generalized Boltzmann equation are discussed treating position and momentum of a particle as classical variables but characterizing the internal state of a molecule by quantum mechanical observables. Using the local part of the collision term only and considering molecules with degenerate, but sufficiently separated internal energy levels one arrives at the Waldmann-Snider equation, which in turn comprises the Waldmann equation for particles with spin and the Wang Chang-Uhlenbeck equation. Special attention is drawn to the case of particles with spin in a magnetic field. Finally, for particles with spin, the local conservation equation for angular momentum, i.e. the Barnett effect (magnetization by rotation) and the antisymmetric part of the pressure tensor are derived from the generalized Boltzmann equation with non-local collision term.
Über das unterschiedliche Ionisationsgleichgewicht wasserstoff- und alkali-ähnlicher Ionen in optisch dünnen Plasmen
Authors: Mahn C.
Published: March 2015

There are many plasmas in which the populations of the various energy states of ions and electrons assume a steady state, but complete local thermal equilibrium is prevented because, on the one hand, radiation absorption is absent and, on the other, the electron density is too low.

Calculations for a plasma without radiation absorption show that: Where hydrogen-like ions are involved it is nearly in order to dispense with detailed calculations and described the ionization equilibrium with the assumption that the collisional ionization processes from the ground state can be equated with the radiative recombination processes to the ground state. For sufficiently low electron densities this leads to the Corona formula.

In the case of other ions, however, neglecting the excited states may result in serious errors. This is because these energy states — unlike those for hydrogen-like ions, which are relatively near the ionization limit — are distributed much more uniformly between the ground state and ionization limit. The implications of this behaviour are discussed with reference to alkali-like ions. A model for the term systems and the collision and radiation coefficients is used to derive the population densities and approximative ionization formulae. According to these the ratio of the densities of the lithium-like O VI ions and the next higher level of ions (O VII), for instance, may differ (for electron densities ne = 5 × 1017 cm–3) from the result of the Corona formula by a factor of 20.
Messung der Zyklotronfrequenz freier Elektronen im Vierpolkäfig
Authors: Gräff G. , Klempt E.
Published: March 2015

Elektrons were stored for several minutes in a homogeneous magnetic field and an electrical quadrupol field V = (U0/R2) · (x2 + y2 — 2z2). The solution of the SCHRÖDINOER equation can be reduced to the problem of three harmonic oscillators. The frequencies of these oscillators were measured experimentally and thus the cyclotron frequency of free electrons was determined.
Über den Zündmechanismus einer fremdausgelösten Niederdruckfunkenstrecke mit Hilfsfunken in der Anode
Authors: Frie W. , Michel A.
Published: March 2015

Der Zündmechanismus einer getriggerten Niederdruckfunkenstrecke mit Hilfsgleitfunken in der Anode beruht im wesentlichen auf der Auslösung von Photoelektronen an der Kathode durch das von dem Hilfsfunken emittierte kurzwellige Licht. Eine Theorie dieses Vorganges wird entwickelt und mit den Meßergebnissen verglichen.
Spezifische Wärme von CeCl3·7 H2O zwischen 1,1 und 3,3°K
Authors: Hüfner S. , Klot R. v. , Küch F. , Weber G.
Published: March 2015

The specific heat of monoclinic CeCl3 · 7 H2O was measured in the temperature range between 1,1 and 3,3°K. Assuming that the cerium-ions are arranged in isolated pairs with isotropic and antiferromagnetic coupling a value of k · 1,20°K is derived from the data for the energy separation between the lower singlet and the upper triplet state.
Level-Crossing-Untersuchung der Hyperfeinstruktur von Sn117 und Sn119 im (5p6s) 3P1
0-Term des Sn I-Spektrums
Authors: Brieger M. , Zimmermann P.
Published: March 2015

Using the level-crossing technique the following relations between the hyperfine structure constant A and the gj value of the (5p6s)3P1
0-term were determined for both the stable isotopes Sn117 and Sn119:

A117 = — 159,57(4) mK · gJ/1,380; A119 = — 167,01(4) mK · gJ/1,380.

From the width of the level-crossing signal a mean lifetime τ = 4,5(7) · 10-9 sec was deduced.
Die Dissoziation des C2-Moleküls durch Rotation
Authors: Messerle G. , Krauss L.
Published: March 2015

The C2-spectrum was excited i low pressure arc with an electrically heated tungstencathode. In this arc the rotational structure of the C2 bands could be followed up to very high rotational quantum numbers. In the c1IIg state a dissociation by rotation was observed. This effect yields D0(C2) = (6,11 ± 0,04) eV. The dissociation by rotation allows the accurate determination of the dissociation energy. Additionally the dissociation products of the IIg states could be fixed unambigously.
Bezug einer Laserfrequenz auf die atomare Frequenz durch Wobbeln
Authors: Spieweck F.
Published: March 2015

A new method for relating the laser frequency to the atomic resonance is described. The piezoelectric mirror mount of a He-Ne laser is fed by a DC and an AC voltage, high enough, so that the laser frequency is scanned over the width Δν of the line profile at threshold. The resulting emission may have a coherence length of the order of 2m. Frequency stability is approximately that of the natural spectral line.
Die Methode der Korrelationsfunktion in der Theorie der Supraleitung
Authors: Lüders Gerhart
Published: March 2015

The formulations developed in previous papers are approximately extended to more realistic models of a metal. After a number of approximations and simplifications earlier results are obtained, but with the electronic mass replaced by the effective mass of the conduction electrons. Boundary conditions at the interface between two metals in electric contact are formulated and discussed with respect to their consequences.
Zur Theorie des Tunneleffekts eines Teilchens im Doppelminimumpotential
Authors: Brickmann Jürgen , Zimmermann Herbert
Published: March 2015

Es wurde die Bewegung eines Teilchens untersucht, das sich in einem Doppelminimumpotential bewegt und durch Tunneleffekt von einer zur andern Mulde gelangen kann. Die Verweilzeiten des Teilchens in den Potentialmulden (a) und (b) wurden für symmetrische und unsymmetrische Doppelminimumpotentiale berechnet.

Zunächst wurden die Eigenlösungen eines Systems untersucht, bei dem ein Übergang des Teilchens zwischen den Mulden unmöglich ist. Dieses entkoppelte System läßt sich durch einen Hamilton-Operator ℋ0 beschreiben, der sich vom Hamilton-Operator ℋ des Doppelminimumproblems durch eine Teilchensperre T im Maximum der Potentialbarriere unterscheidet. ℋ0 setzt sich aus zwei kommutierenden Operatoren ℋ(a) und ℋ(b) zusammen, deren Eigenfunktionen jeweils nur über einen der Bereiche (a) oder (b) nichtverschwindende Amplituden aufweisen. Ein Eigenzustand von ℋ0 beschreibt somit ein Teilchen, das mit Sicherheit in einer der Mulden anzutreffen ist. Das gilt ebenso für eine beliebige statistische Mischung der Eigenzustände von ℋ(a)oderℋ(b). Damit kann für eine Gesamtheit von N0 Teilchen eine Anfangsbedingung formuliert werden, nach der zu einer bestimmten Zeit t0 sämtliche Teilchen z. B. in der Mulde (a) lokalisiert sind. Die zeitliche Änderung der statistischen Mischung wird nicht durch den Hamilton-Operator ℋ0, sondern durch ℋ bestimmt. Damit nimmt bei Anwendung des ℋ-abhängigen, unitären Operators U (t, t0) auf den statistischen Anfangszustand die Wahrscheinlichkeit W(b) (t), ein Teilchen für t > t0 in der Mulde (b) zu finden, einen endlichen Wert an. Die Zeit t′, nach der W(b) (t) erstmal seinen zeitlichen Mittelwert W̄(b) annimmt, ist dann charakteristisch für die Teilchenbewegung zwischen den Mulden. Die wahrscheinliche Verweilzeit τ(a) eines Teilchens in der Mulde (a) ist dann näherungsweise zu τ(a) = t′/ W̄(b) gegeben. Die Beziehung stimmt im Falle eines symmetrischen Doppelminimumpotentials mit früheren Rechnungen überein. Im Falle unsymmetrischer Potentiale ist sie zur Bestimmung von Verweilzeiten besser geeignet als die quasiklassische Methode.
Scattering of Electromagnetic Waves by Turbulent, Weakly Ionized Plasmas
Authors: Kröll W.
Published: March 2015

The scattering of a plane, monochromatic electromagnetic wave by the fluctuations of the dielectric constant of a turbulent weakly, ionized plasma is investigated on the basis of the statistical theory of locally isotropic tubulence. The effects of collisions on the fluctuating dielectric constant of the electrons are taken into account. The spectral density determining the scattering cross section is related to the structure functions of the fluctuations of the electron concentration and the temperature. These structure functions are calculated from the transport equations with the use of methods developed in the statistical theory of strong turbulence.
Bildungsgesetze der Kernsignale in Festkörpern bei Impulsexperimenten
Authors: Siegle G.
Published: March 2015

Free induction transient signals in nuclear magnetic resonance are calculated for solids extending the method of Lowe and Norberg to several pulses. A general formula is given for the nmr signals after 1, 2 and 3 pulses applicable to substances with spins I= 1/2. It contains 9 different types of signals and in very compact form the dependences of the signal amplitudes on experimental parameters — on the phases of the modulation, lengths and distances of the pulses and on the deviation of the exact resonance. Earlier theoretical and experimental results are shown to be included. The most important parts of the formula are checked by experiments.

The formula is a good approximation only near the maxima of the signals and must be extended in order to describe the shape of the signals in detail.
Photoionisationsuntersuchungen an Atomstrahlen
Authors: Comes F. J. , Speier F. , Elzer A.
Published: March 2015

An experiment to determine the absolute value of the photoionization cross section of atomic oxygen is described. The atoms are produced in an electrical discharge in oxygen gas with 1% hydrogen added. In order to prevent recombination a crossed beam technique is employed. The ions formed are detected by a time-of-flight mass spectrometer. The concentration of oxygen atoms in the beam is 57%.

The measured photoionization cross section of atomic oxygen is compared with theoretical data. The results show the participation of autoionization processes in ionization. The cross section at the autoionizing levels detected is considerably higher than the absorption due to the unperturbed continuum. Except for wavelengths where autoionization occurs the measured ionization cross section is in fair agreement with theory. This holds up to 550 Å whereas for shorter wavelengths the theoretical values are much higher.
Photoionisationsuntersuchungen an Atomstrahlen
Authors: Comes F. J. , Elzer A.
Published: March 2015

The photoionization cross section of atomic nitrogen has been measured between the ionization limit and 432 A. The experimental values are well fitted by those from a calculation of Henry due to the dipole velocity approximation. A Rydberg series converging to the 5S-state of the ion is clearly identified from the ionization measurements and is shown to ionize.
Mikrowellen-Relaxation von Decylalkohol in Mischung mit unpolaren Flüssigkeiten
Authors: Klages G. , Roth N.
Published: March 2015

An reinem n-Decylalkohol, sowie seinen konzentrierten und verdünnten Lösungen in vier unpolaren Flüssigkeiten wurde zwischen 20 und 60°C die komplexe DK bei 9,4,19,5 und 34,8 GHz gemessen. Wenn man die Anteile abtrennt, die das Hauptabsorptionsgebiet bei diesen Frequenzen noch beiträgt, erhält man ein Mikrowellengebiet anomaler Dispersion, das allein von Prozessen mit Kurzzeitrelaxation herrührt. Dazu gehört eine Verteilung von Relaxationszeiten, die in erster Näherung durch zwei diskrete Werte zu beschreiben ist. Die so erhaltenen charakteristischen Daten — Dispersionsstufe, Relaxationszeit und Aktivierungsenergie — werden von sehr verdünnter Lösung, die nur Einzelmoleküle enthält, bis zur reinen Dipolflüssigkeit verfolgt und geben bei der Diskussion Hinweise auf die zugrundeliegenden molekularen Vorgänge. Danach ist die kürzeste Zeitkonstante der Eigenbewegung von polaren Molekülgruppen zuzuordnen, in verdünnter Lösung allein der OH-Gruppe. Die Dipolorientierung mit längerer Relaxationszeit dagegen hat quantitativ alle Kennzeichen, die von der rotatorischen Bewegung ganzer, starrer oder flexibler Moleküle bekannt sind. Zu ihr müssen bei konzentrierten Mischungen aber noch andere Strukturen beitragen als allein Monomere, wie aus dem Relaxationszeitspektrum des Einzelmoleküls in verdünnter Heptanlösung folgt. Bei Benzol treten durch eine spezifische Wechselwirkung mit der OH-Gruppe erhebliche Verschiebungen in der Relaxationszeit-Verteilung auf, die sich noch bei höheren Alkoholkonzentrationen bemerkbar machen.
Self-Diffusion in Molten Lead Bromide
Authors: Sjöblom C.-A. , Andersson J.
Published: March 2015

The self-diffusion coefficients of both ions in molten PbBr2 have been measured with a modification of the porous-frit technique1-3. The results can be described with Arrhenius relations:

DPb=7.4 × 10-4 exp(-6500±900)/RT (380-540°C),

DBr=8.3 × 10-4 exp(-6100±700)/RT (380-555°C).

D is expressed in cm2s-1, R in cal · mole-1 degree-1 and T in degrees Kelvin. The relative merits of different experimental techniques are discussed and a comparison between the (experimental) external transport number and the corresponding calculated quantity using Laity’s “new formalism” is made.
Mikrowellenspektrum, Hinderungspotential der internen Rotation, Dipolmoment und Quadrupolkopplungskonstanten des N-Methylpyrrols
Authors: Arnold W. , Dreizler H. , Rudolph H. D.
Published: March 2015

Das Mikrowellenspektrum des N-Methylpyrrols und des D3-N-Methylpyrrols wurde untersucht, um das niedrige Hinderungspotential der internen Rotation der Methylgruppe zu bestimmen. Mit dem Spektrum sind jeweils zwei unterschiedliche Sätze von Potentialparametern V6 und V12 verträglich. Ferner wurden das Dipolmoment und die Quadrupolkopplungskonstanten bestimmt.
Lebensdauern und Löschquerschnitte elektronisch angeregter Zustände von N2O+, NO, O2
+, CO+ und CO
Authors: Fink E. H. , H. Welge K.
Published: March 2015

Radiative lifetimes of electronically excited states of N2O+, NO, O2
+, CO+, and CO are measured by means of the phase-shift method. Excitation is performed by a modulated electron beam. Phase references are derived from He I, N2
+, and CO+ transitions as well as from another independent method based on the very short decay time of the air fluorescence.

Measurements are performed on the transitions

N2O+ (B2 ∑u
+ ➝ X2 IIg), NO (A2 ∑+ ➝ Χ2 II), O2
+ (b4 Σg
- ➝ a4 IIu),

O2
+ (A2 IIu ➝ X2 IIg), CO+(B2 ∑ ➝ X2 ∑), CO+ (B2 ∑ ➝ A2 II) ,

CO+ (A2 II ➝ X2 ∑), CO (b3 ∑+ ➝ a3 II), CO (B1∑+ ➝ A1 II).

As far as feasable lifetimes of individual vibrational levels are measured. From the pressure dependence of the decay rates cross-sections for the quenching of the excited states by the parent molecules are obtained.
Theory of Radiative and Nonradiative Electronic Processes in Ionic Crystals with Point Imperfections
Authors: Rampacher Hermann
Published: March 2015

After an outline of the quantum theory of decaying states on the basis of the resolvent method. a Hamiltonian is considered describing an ionic micro-crystal containing one electronic impurity center. The complete Hamiltonian of the coupled system micro-crystal plus radiation field can be decomposed into a diagonalized part and a “perturbation”, so that the perturbation leads to terms associated with nonradiative electronic transitions, anharmonic lattice transitions, radiative electronic transitions, and radiative lattice transitions. The state of the system micro-crystal plus radiation field is supposed to be given by a density operator in the representation where the unperturbed Hamiltonian is diagonal. By means of the assumption of initial random phases the quantum theory of decaying states yields an approximatively valid differential equation for the diagonal elements of the density operator describing the time-dependent radiative and nonradiative electronic processes in the micro-crystal. Under certain additional conditions the differential equation has the form of the Pauli-Master-Equation.
Eine stationäre zylindersymmetrische Lösung der Plasmagleichungen im eigenleitenden Halbleiter mit gleichen Beweglichkeiten der Ladungsträger
Authors: Handel P. H. , Iacomi R. S. , Naumescu M.
Published: March 2015

Die Verteilung der Ladungsträger über den Querschnitt eines in bezug auf Elektronen und Löcher symmetrisch angenommenen, stromdurchflossenen Halbleiterdrahtes wird analytisch berechnet. Zugleich lassen sich Magnetfeld und Temperatur analytisch und graphisch ausdrücken. Dabei wurden die Rekombination der Ladungsträger, das eigene Magnetfeld des Stromes sowie die Wärmeleitung mit in Betracht gezogen. Die hier erzielte Näherung ist gerade im Fall großer Rekombinationsgeschwindigkeit und hoher Beweglichkeiten anwendbar, in dem andere analytische Lösungsmethoden nicht den Voraussetzungen entsprechen. Man bemerkt einen Anstieg der Trägerkonzentration an der Zylinderachse, dem aber die Rekombination dämpfend entgegenwirkt.
Das elektrische Potential einer Punktladung in einem inhomogenen Medium
Authors: Hoch K.
Published: March 2015

Es wird das elektrische Potential einer Punktladung berechnet, die sich in einem Medium mit einem Gradienten der Dielektrizitätskonstanten befindet. Das Potential läßt sich mit einer Integral- oder Reihendarstellung angeben.
Elektronenbeugung an Quarz
Authors: Dudek H. J. , Schüz W.
Published: March 2015

Es wird über Elektronen-Feinbereichsbeugung an Quarzeinkristallsplittern berichtet. Beobachtet wurde eine ringförmige Anordnung von Reflexen. Die auftretenden verbotenen Reflexe werden diskutiert.
A Note on the Evaluation of Nuclear Quadrupole HFS Multiplet Patterns of Molecular Rotational Transitions
Authors: Rudolph Heinz Dieter
Published: March 2015

The intensity weighted mean over the nuclear quadrupole hyperfine structure multiplet of a molecular rotational transition yields, to first order, the “undisturbed” rotational transition frequency. This fact may serve to effectively separate the two interrelated problems of calculating the rotational constants of the molecule from the “undisturbed” frequencies and the nuclear quadrupole coupling parameters from the multiplet splitting patterns.
Photographical Record of the Dispersion Surface in Rotating Crystal Electron Diffraction Pattern
Authors: Lehmpfuhl G. , Reissland A.
Published: March 2015

Strong interacting wave fields in a wedge-shaped crystal are separated into different plane waves when leaving the crystal and reveal points on the dispersion surface. By rotating the crystal while moving the film one obtains a photographical record of a section through the dispersion surface which may be compared with theory. An experiment with a macroscopic MgO wedge is reported. The 002 interference with excitation error nearly zero was recorded near the [I10] zone axis while rotating the crystal about the [001] axis. The diagrams are compared with dynamical 17-beam calculations. The results show that a reduction of the infinite dynamical system of equations to 17 equations is correct under these special geometrical conditions.
Hyperfein- und Superhyperfeinstruktur der Elektronenspinresonanz und die chemische Bindung in Kupfer(II)-Natrium-Chlorophyllin
Authors: Schoffa G.
Published: March 2015

Die Spektren der Elektronenspinresonanz des Kupfer-Natrium-Chlorophyllins in Methanol zeigen eine Hyperfeinstruktur vom Kupferkern und eine Superhyperfeinstruktur von vier Stickstoffkernen am Porphyrinring. Bei Raumtemperatur findet man mit g0=2,1077, A0
Cu =- 98 · 10-4 und

A0
N = -14·10-4 cm-1 ein anderes Spektrum als bei 77 °K mitg∥= 2,2033, g⟂=2,0518,

A∥
Cu = -205·10-4 cm-1, A⟂
Cu ∼ - 30 · 10-4 cm-1, A∥
N = -15,9 · 10-4 cm-1.

Durch die Verknüpfung dieser Meßwerte mit den Koeffizienten für die Linearkombination der Atomeigenfunktionen, die die chemische Bindung in Kupferkomplexen beschreiben, erhält man für die dσ-Bindung α=0,91 und α′=0,51. Zur Berechnung der Linearkoeffizienten für die dπ-Bindung in der Porphyrinebene (β) und außerhalb dieser Ebene (δ) wurde aus den optischen Messungen ΔExy und ΔΕxy erhalten und mit diesen Werten aus den ESR-Spektren β=0,81 und δ=0,85 berechnet. Hiermit ist in Cu-Chlorophyllin die da-Bindung stark ionisch, die dπ-Bindung ebenfalls, jedoch senkrecht zur Porphyrinebene stärker ionisch als in der Porphyrinebene.
Kernmagnetische Resonanzsignale in Festkörpern mit zwei verschiedenen Spinsorten
Authors: Siegle G.
Published: March 2015

In solids containig spins I=1/2 only, the NMR-transients in solids are given approximately by formulas derived earlier1. They can be extended to solids with a second, but nonresonant kind of spins S using a simple substitution. The results are exact to second order in the pulse distances and include the dependences of the signal amplitudes on experimental parameters e. g. pulse lengths etc.

If the phases of the modulation of two 90°-pulses differ by 0° or 90°, a calculation up to the fourth order yields approximations of the shapes of the resulting echoes 2. It is shown that the sum of these echo amplitudes in certain cases agree with the shape of the free-induction-decay3 after a single pulse. If the spins S fluctuate rapidly with respect to the Larmor period the echo amplitudes show a strong dependence on variations of the external Zeeman field and the temperature. The results are checked by experiments.
Zur Lösung des quantenmechanischen Drei-Körper-Problems
Authors: Ruder H.
Published: March 2015

For the description of a three-body-system 6 coordinates are introduced which take full advantage of the symmetry properties of the system. The Schrödinger equation in these coordinates is derived. Using rotational and reflection symmetry one obtains a set of l respectively l+1 coupled differential equations containing only the 3 coordinates of the triangle formed by the 3 masses. Solutions are given for special potentials and arbitrary l. The physical meaning of the differential operators appearing in the equations becomes evident from their application to the solution functions. This leads to a rearrangement of the Hamiltonian in a very transparent form and gives a hint how to get the most effective perturbation expansion. A simple example is worked out. For systems with Coulomb interaction a modification of the method is suggested by physical considerations. The calculation of the ground state energy of the Helium atom shows the rapid convergence of the procedure.
Zum Streumechanismus in hochdotierten Halbleitern des Systems Bi-Te-Se
Authors: Heldmann W. , Klügel J.
Published: March 2015

Aus dem Verhältnis von Nernst-Koeffizient zu Hall-Beweglichkeit ist es möglich, unter gewissen Voraussetzungen eine direkte Aussage über die Art der Ladungsträgerstreuung zu erhalten. Es werden die Einflüsse von Entartung und Anisotropie diskutiert und das Ergebnis mit Messungen an Kristallen der Halbleiterlegierung Bi2Te2,7Se0,3 verglichen.
Optical Determination of Thermal Conductivity with a Plane Source Technique
Authors: Gustafsson Silas E. , Halling Nils-Olov , Kjellander Rolf A. E.
Published: March 2015

The thermal conductivity and the thermal diffusivity of the three alkali nitrates LiNO3 , RbNO3 and CsNO3 have been measured over a temperature range between 50° and 100 °C above their melting points. Any temperature dependence of the thermal conductivity cannot be established for any of the investigated liquids but the results indicate that it must be less than 10-3 °C-1. The experimental results are compared with the conductivities which can be calculated with already excisting theories. A somewhat modified theoretical approach is suggested for estimating the thermal conductivity, where no adjustable parameters are being used. The experimental and theoretical values at the melting points agree within about 10 percent.
Über die Anwendbarkeit der Linienumkehrmethode zur Messung der Elektronentemperatur in einem schwach ionisierten Edelgas-Alkali-Plasma
Authors: Riedmüller W. , Brederlow G. , Salvat M.
Published: March 2015

When an electric current is passed through a rare-gas alkali plasma the electron temperature rises above the gas temperature. This effect was investigated in a streaming argon-potassium plasma at atmospheric pressure and a gas temperature of 2000 °K. The applicability of the line reversal method to the measurement of the electron temperature has been investigated. General conditions under which the electron temperature equals the line reversal temperature have been derived. In the case studied, the plasma had to be optically thick for the resonance radiation used. The electron temperature was measured with this method as a function of the current density. The results were compared with the values calculated from the theory and with the values calculated from the also measured conductivities. For electron temperatures above 2400 °K all three give the same results.
Numerische Untersuchungen charakteristischer Größen eines Plasmamodells
Authors: Wilke Karlheinz
Published: March 2015

A fully 3-dimensional plasma consisting of up to 96 charged particles is simulated in a computer. The plasma is confined to a sphere (or cube) with specularly reflecting walls. The forces are computed using a predictor corrector method with variable time steps. From initial configurations randomly chosen the evolution of the plasma is followed numerically. Distribution functions and moments with respect to various phase variables are obtained as time averages: the distribution of velocity, kinetic and potential energy, of the electric microfield, the micropotential as measured at a neutral point of reference (usually the center of the system) , the mean square electric field, the microfield correlation function and the particle relaxation times. As the sphere used in the experiments has dimensions only slightly larger than the Debye sphere, collective phenomena and those due to major density fluctuations cannot be expected. Despite these limitations the mean electric field is found to be high by approx. 10% compared to the Holtsmark field. Furthermore other comparisons to existing theories with respect to the variables already mentioned are carried out.
Innermolekulare Beweglichkeit von Dicarbonsäureestern und dielektrische Relaxation
Authors: Nasuhoglu R.
Published: March 2015

An der homologen Reihe der Diäthylester und einigen verwandten Molekülen wurde ε″ zwischen 30 und 0,7 cm Luftwellenlänge in verdünnter Benzollösung gemessen. Dem so ermittelten Teil der Absorptionskurve läßt sich ein Relaxationszeitspektrum nach Fröhlich zuordnen, dessen Mittelwert für Bernsteinsäurediäthylester größer als bei allen anderen Homologen ist. Das geht parallel zu einem besonders niedrigen molekularen Dipolmoment und wird als innere sterische Behinderung der Rotation von polaren Gruppen gedeutet. Bei Dicyclohexyl- und Dibenzyloxalat sind die Absorptionskurven unsymmetrisch, woraus auf die Beteiligung von sehr kurzen Relaxationszeiten an der Dipolorientierung geschlossen wird.
Die Änderung der Wärmeleitfähigkeit von ferromagnetischen Nickel-Kupfer-Legierungen im Magnetfeld
Authors: Burger R. , Dittrich H. , Koch K. M.
Published: March 2015

Die Änderung der Wärmeleitfähigkeit λ von Ni und Ni—Cu-Legierungen im Magnetfeld verläuft unterhalb der magnetischen Sättigung völlig parallel zur Änderung der elektrischen Leitfähigkeit σ. Oberhalb der Sättigung nimmt λ sowohl bei H parallel als auch bei H senkrecht zum Wärmestrom mit zunehmendem H ab, wogegen σ zunimmt. Dieser Effekt wird mit dem experimentell beobachteten Anstieg von λ oberhalb des Curie-Punkts und mit der magnetischen Beeinflußbarkeit der spez. Wärme in Zusammenhang gebracht.
Experimentelle Untersuchungen an einem Wasserstoff-Lichtbogen im achsenparallelen Magnetfeld.: II. Feldstärke und Geschwindigkeitsmessungen mit Potentialsonden
Authors: Mahn C. , Ringler H. , Zankl G.
Published: March 2015

The axial and radial components of the electric field in a hydrogen arc with superimposed axial magnetic field have been measured with potential probes.

The axial field was found to be only 3.1 V/cm, whereas in the radial direction fields up to 400 V/cm indicate a rotation of the arc. Radial fields are caused by υ x 23 e. m. forces due to this rotation.

The probe measurements indicate velocities of the order of 106 cm/sec which are confirmed by Doppler shift measurements. A simple model is considered in which Lorentz forces cause a rotation of the arc; calculations are in agreement with the measurements.

Axial velocities (2 · 104 cm/sec) have also been determined, by measuring the velocity of a perturbation due to the probe. This perturbation travels downstream in the arc and is observed as a small drop in the arc voltage passing the anode region.
Die Spektroskopie des Wasserstoffmoleküls in der Nähe seiner Ionisierungsgrenze
Authors: Comes F. J. , Wellern H. O.
Published: March 2015

The absorption and ionization cross sections of molecular hydrogen for the wavelength region from 850 to 792 A are given. This region contains the dissociation and ionization limit as well. The rotational structure of the bands could partially be resolved in this experiment. As the dissociation of the molecule results in an excited hydrogen atom, this process can be followed by measuring the atomic fluorescence. Part of the excited atoms is found to be in the metastable 2 2S-state. From fluorescence as well as absorption and ionization measurements it can be shown, that even above the ionization limit the absorption due to the D-state of the molecule leads to dissociation. The experimental results seem to point out, that the spectroscopic value of the ionization limit has to be shifted to lower energies.
Methode zur Bestimmung des Anfangstransportes bei Trennrohren mit Entnahme
Authors: Trötsch E. , Dickel G. , Fritzsche H.
Published: March 2015

Es wurde das Verhalten einer Trennrohrstaffel theoretisch und experimentell untersucht, bei der an einer Stelle die Breitenfunktion gegen das Entnahmeende hin zunimmt. Dieser Sachverhalt hängt eng mit dem Effekt zusammen, daß bei großen Entnahmen unter Umständen der Konzentrationsgradient in der Längsrichtung in Teilen der Anlage seine Richtung umkehren kann. Es zeigt sich, daß man daraus eine exakte Methode zur Bestimmung des Anfangstransportes herleiten kann.
Diffusion und Druckdiffusion in Gasen bei hohen Drucken
Authors: Richter Joachim
Published: March 2015

Betrachtet werden zwei druckfeste Kammern, die durch eine Kapillare miteinander verbunden sind und mit einem Gasgemisch aus zwei Komponenten verschiedener Konzentration gefüllt sind. Der Konzentrationsunterschied ruft Diffusion hervor, die durch die damit verbundene Schwerpunktsverschiebung und durch den Einfluß der Kapillare mit der Zeit einen Druckunterschied aufbaut. Die dadurch verursachte Druckdiffusion wirkt der Diffusion entgegen. Es wird die Möglichkeit aufgezeigt, den Diffusionskoeffizienten und den Druckdiffusionskoeffizienten aus einem Experiment zu bestimmen. Das Problem wird unter Vorgabe von drei verschiedenen Konzentrationsverteilungen zu Beginn des Versuchs berechnet. Es wird ferner gezeigt, daß unter gewissen Annahmen diese verschiedenen Anfangsbedingungen keinen Einfluß auf das Ergebnis haben. Diffusions-, Druckdiffusionskoeffizient, partielles Molvolumen und Molvolumen der Mischung werden bei der Berechnung als unabhängig von Zusammensetzung und Druck angenommen.
The Electrical Conductivity of (Tl-Rb)NO3 and (Na-Rb)NO3
Authors: Wagner Vittoriano , Forcheri Sandro
Published: March 2015

The electrical conductivity of molten (Na—Rb)NO3 and (Tl—Rb)NO3 was determined.

While the equivalent conductivity of the first system shows the usual negative deviation from additivity, that of the second one varies nearly linearly with composition.

After discussing the conductivity isotherms in terms of some proposed models, an excess conductivity isotherm is presented, derived on the basis of simple assumptions about the trend of both cationic mobilities.
On the Decay of 165Dy
Authors: Bashandy E. , Ibrahiem N. , El-Sayad G.
Published: March 2015

The internal conversion electron spectrum of transitions in the decay of (139 min) 165Dy to 165Ho has been studied using a high resolution iron-free double focusing β-ray spectrometer. In addition to γ rays previously reported eight new γ rays, mostly in the low energy region, have been observed. A decay scheme involving 17 excited levels is proposed for 165Ho. Multipolarity data, obtained from the measurements of absolute or ratios of conversion coefficients of γ rays, were utilized for assigning possible spins and parities to the levels of 165Ho. The experimental level structure is discussed in the light of nuclear models.
Optische Anregung beim Ladungsaustausch von Edelgasionen für Stoßenergien von 5 bis 300 eVolt
Authors: Schlumbohm H.
Published: March 2015

Measurements of the photoemission caused by collisions of ground level He+- and Ne+-ions with Ar- and Kr-atoms have shown several multipletts of Ar II and Kr II within the investigated wavelength range of 3500 to 5500 A. At a high rate the charge transfer processes occur into excited states of Ar* and Kr*. The reactions are endothermic with a deficit of internal energy between 6 and 19 eV.

The cross sections measured for several chosen transitions start at characteristic threshold energies between 10 and 25 eV. Above the threshold the cross sections rise slowly with increasing energy when Ne* is the colliding ion and very fast for He+. Above 50 to 100 eV the cross sections show nearly constant values. — The minimum kinetic energy values are calculated, which can just fill up the deficits of internal energy, and are shown to be equal to the measured threshold energies. Thus it follows that the pseudo-crossing of the potential energy curves of the quasimolecules occurs at an energy value equal to the asymptotic level of the above curve.
Das Mikrowellenrotationsspektrum des SnTe
Authors: Hoeft J. , Tiemann E.
Published: March 2015

Im Frequenzbereich 12—19 GHz wurden bei Temperaturen um 650 °C Rotationsübergänge von 27 isotopen Molekeln des SnTe gemessen. Es werden Rotationskonstanten, Kernabstände, Koeffizienten der Potentialfunktionen nach DUNHAM und MORSE sowie Massenverhältnisse von Zinn- und Tellurisotopen mitgeteilt. Als Mittelwert für den Gleichgewichtsabstand der Kerne ergibt sich re = (2,522 804 ± 0,000 029) Å.
Zur Torsions-Schwingungs-Rotationswechselwirkung in Rotationsspektren
Authors: Dreizler H.
Published: March 2015

Zur Analyse der Torsionsfeinstruktur von Rotationslinien in schwingungsangeregten Zuständen wird ein Molekülmodell diskutiert, das drei Rotations-, einen Torsions- und einen Schwingungsfreiheitsgrad besitzt. Die theoretische Formulierung ist eine Verallgemeinerung der bekannten Principal Axis Method für Molekülmodelle ohne Schwingungsfreiheitsgrad. Bei bekannter Schwingungsfrequenz tritt nur ein weiterer Potentialparameter auf.
Coupled Translational and Rotational Motions of a Sphere in a Fluid
Authors: Hess Siegfried
Published: March 2015

Starting from the exact steady state Navier-Stokes equation and taking the quadratic inertia term into account in an appropriate way one can show the existence of a coupling of the translational and rotational motions of a rigid sphere in an incompressible fluid. No-slip boundary conditions are used. The coupling consists in a transverse force proportional to the cross product of the linear and angular velocities of the sphere. This force is closely related to the Magnus effect. It is of interest for the theory of Brownian motion of particles with internal degrees of freedom.
Notizen: Determination of Cosmogenic Production Rates of Be-10 and Be-7 in the Atmosphere from Activity Measurements in Soil Layers
Authors: Moeller P. , Wagner K.
Published: March 2015

The cosmogenic production rates of Be-10 and Be-7 in the atmosphere have been derived from activity measurements of the Be-isotopes in soils. The ratio of the spallation yields was found to be Be-10/Be-7 =0.7 ±0.3.
A Plane Source Method for Measuring Interdiffusion Coefficients of Transparent Liquids
Authors: Gustafsson Silas E. , Wallin Lars-Erik , Arvidsson Torkel E. G.
Published: March 2015

A bottom layer diffusion technique is described, where an experiment is initiated by dropping a crystal of the diffusing substance to the bottom of a properly designed container for the liquid. It is shown that this technique is comparable to any other method from point of view of accuracy while the experimental procedure is extremely simple. The technique is tested at room temperature on two aqueous solutions with widely different diffusion coefficients. It is also applied to the determination of the interdiffusion coefficient of the silver ion in the three molten salts: sodium, potassium, and rubidium nitrate.
Quantitative Untersuchung einer Fallout-Probe des chinesischen Kernwaffentests vom 28.12.1966
Authors: Allkofer O. C. , Hauser H. , Meyerbröker H. , Simon M. , Wöhren C.
Published: March 2015

A quantitative total analysis of β- and γ-ray emitting radionuclides of a representative radioactive fallout-sample from the chinese nuclear test of 28 Dec. 1966 is presented. The different methods to identify the fission-products and induced radionuclides such as U-237 and Np-239 are described.

Measurements of the concentrations of the fission-products and of the induced radionuclides U-237 and Np-239 make it probable that the chinese nuclear test of 28 Dec. 1966 was a fusion bomb with added fission of U-238.
Zur Berechnung der Zentrifugaldehnungskonstanten ταβγδ
Authors: Klauss K. , Strey G.
Published: March 2015

Ausdrücke für die Ableitungen des Trägheitsmomententensors Iαβ nach den Symmetriekoordinaten eines Moleküls werden angegeben und diskutiert.
Electron Spin Resonance of Fluorinated Benzophenone Anion Radicals
Authors: Fischer P. H. H. , Zimmermann H.
Published: March 2015

Electron spin resonance spectra have been observed for anion radicals derived from 4-fluorobenzophenone, 2-fluorobenzophenone, 4,4′-difluorobenzophenone, 3,3′-difluorobenzophenone and decafluorobenzophenone. All radicals have been generated by electrolytic means in dimethoxyethane-acetonitrile mixtures. In the case of the mono- and difluorinated species, interpretation of the spectra as arising from the corresponding anion radicals is possible. In the case of decafluorobenzophenone, the anion radical cannot be the species giving rise to the spectrum.
Einfluß der Nahordnung um Magnesiumverunreinigungen in Metallschmelzen auf die Kernresonanzfluoreszenz-Ausbeute
Authors: Holtmeyer Günther , Kalus Jürgen
Published: March 2015

Die relative KRF-Ausbeute am 1,37 MeV-Niveau des Mg24 wurde für Mg-Verunreinigungen in den flüssigen Metallen Li, Na, Sr, Sn, Pb, Bi gemessen. Es wurde versucht, Aussagen über die Flüssigkeitsstruktur zu gewinnen. Dazu wurde ein Modell über die Abbremsung beschleunigter Fremdatome in sonst reinen Substanzen entwickelt, das von Hart-Kugel-Stößen ausgeht und den Vielteilchencharakter des Stoßproblems dadurch berücksichtigt, daß eine außerhalb des harten Stoßes erfolgende Abbremsung des stoßenden Teilchens an Potentialschwellen eingeführt wird.

Es ergibt sich ein Zusammenhang zwischen KRF-Ausbeute, Verlagerungsenergie und Nahordnung (Koordinationszahl) . Die Ergebnisse weisen darauf hin, daß für Alkalimetalle im Gegensatz zu anderen Metallen eine Verlagerungsenergie im 10 eV-Bereich anzunehmen ist.
Diagram Approach to the Theory of Collisionless Plasma Turbulence
Authors: Biskamp D.
Published: March 2015

From the Vlasov equation written as a nonlinear equation for the distribution function ƒ, a perturbation expansion of the fluctuating part of ƒ, ƒ̃̃=ƒ — 〈ƒ〉, is carried out in terms of the linear solution using a diagram representation similar to that of Wyld. From this a diagram expansion is obtained for the correlation function U=〈ƒ̃ƒ̃̃〉 and similar diagram series for two auxiliary functions, the averaged linear response function G=〈Ĝ〉 and the generalized vertex function Γ. Approximate asymptotic equations for U imply the summation of appropriate infinite subsets of diagrams. To derive such approximations two criteria are applied: 1) Consistency with the basic conservation laws (particle number, momentum, energy); 2) Selection of diagrams analogous to those leading to good approximations in Kraichnan’s random oscillator problem, the principal results of which are regained. Contrary to Wyld’s summation procedure diagram summation are not carried out directly in the expansion of U, but in the expansions of the functions 〈ƒ̃ƒ̃ƒ̃̃〉 and 〈ƒ̃̃ Ĝ〉, which appear on the right hand side of the differential equations for U and G. This automatically guaranties the validity of the conservation laws. The first approximation we discuss, which is equivalent to the quasi-Gaussian approximation well known from hydrodynamic turbulence, leads to the kinetic wave equation of weak turbulence. The next approximation consists of a coupled set of equations for U and G which are identical with the equations of the symmetrical random coupling model of Orszag and Kraichnan. The third approximation derived implies the generalized vertex function Γ. The first and the third of these approximations cannot be obtained in Wyld’s summation scheme. On the other hand it does not seem possible to derive the third approximation for the nonlinear Vlasov equation using Kraichnan’s diagram technic.
Ionization of Helium Near Threshold by Electron Impact
Authors: Krige G. J. , Gordon S. M. , Haarhoff P. C.
Published: March 2015

The ionization threshold of helium has been studied experimentally using the retarding potential difference technique. The cross section for the formation of He+ is nonlinear for at least the first 2 eV above threshold, in agreement with recent results obtained by Brion and Thomas using a 127° electrostatic energy selector.
Transmission of a Lorentzian Spectral Line Through a Layer of Lorentzian Absorbers. Part I
Authors: Heberle Juergen , Franco Sergio
Published: March 2015

This paper is concerned with the evaluation of the integral that represents the total transmitted intensity. We consider the general case in which the thin-absorber linewidth ΓA is allowed to be different from the linewidth ΓS of the source. The introduction of the parameter γ = ΓA/ΓS has made it possible to expand the integral in an infinite series, each term of which is a rational algebraic expression. Our formulation avoids the tedium of numerical integration and lends itself readily to programming in FORTRAN. The application to Mössbauer spectroscopy is discussed. The results are valid in the case of a split source even if the spacing between the emission lines is less than their linewidth.
Zur phänomenologischen Begründung erweiterter Casimir-Onsagerscher Reziprozitätsbeziehungen
Authors: Muschik W.
Published: March 2015

Attempts are made to give phenomenological reasons for nonlinear Casimir-Onsager reciprocal relations. The fluxes can be defined as time derivations of state variables, or they can be explained by means of balance equations, because only their vectorial properties are used. At first, time reversal is replaced by an abstract parameter reversal from which involutoric transformations of forces and fluxes result. The connection between the parameter reversal of forces and fluxes allows to give reasons for relations which are equal to the Casimir-Onsager reciprocal relations apart from a sign. This sign is determined by experience. The connection between parameter and time reversal is discussed.
Internal Acoustic Gravity Waves
Authors: Mclellan Alden , Winterberg F.
Published: March 2015

An exhaustive analysis of wave motion in a compressible isothermal medium under the influence of gravity is presented. The dispersion relation governing the wave propagation is derived from the linearized equations of fluid dynamics and thermodynamics, and it is arranged in a nondimensional form. Penetration depths, frequency cutoffs, and particle orbits are calculated under the assumption of an ideal gas. With the nondimensional form of the dispersion relation these data can be expressed in a form independent of the constants describing a particular atmosphere. The results can be conventiently displayed on a number of diagrams valid for monatomic and diatomic gases. Dissipative effects arising from viscosity and heat conduction are neglected.
Theoretische Untersuchungen zur Strömung im glatten Rohr
Authors: Frie Wolfgang
Published: March 2015

Unter Benutzung des vollständigen Ansatzes für den Zusammenhang zwischen der Schubspannung und dem Geschwindigkeitsgradienten wird durch eine plausible Festlegung der radialen Verteilung des Mischungsweges und durch Einführung eines „Turbulenzgrades“ als Anregungsgesetz für die turbulente Energie eine analytische Lösung hergeleitet, die das Strömungsverhalten im glatten Rohr für alle Reynolds-Zahlen beschreibt. Diese Lösung enthält das Hagen-Poiseuille-sche Gesetz der laminaren Strömung und das Prandtl-v. Kármánsche Gesetz der turbulenten Strömung als Grenzfälle, gibt aber auch das Übergangsgebiet recht gut wieder.
Zum kollektiven Anteil des Plasma-Mikrofeldes
Authors: Hunger K. , Larenz R.W.
Published: March 2015

The Holtsmark microfield evaluation is rediscussed. It is shown that in the usual computation of the Fourier transform a term is neglected which has the dimension of a dipole moment density. This term occurs only for long range forces (here Coulomb ones) and remains undetermined in the limit of an infinitely large system without interaction. Furthermore, it is sensitive to deviations from ergodicity. The true microfield distribution results as a Holtsmark distribution centered at the generally nonvanishing far field. As the distribution of the latter is Gaussian the complete distribution results as a convolution of the Holtsmark distribution with that of the far field. The parameter of the Gaussian far field distribution is computed for a non interacting plasma consisting of N charges, by taking into account explicitely the collective field of space charge fluctuations. The formulae arrived at with respect to the microfield as well as the micropotential suggest to perform numerical computer experiments (HUNGER, LARENZ and WILKE, to be published). For an interacting plasma, the far field is obtained qualitatively. It agrees with the microfield of HUNGER and LARENZ (1961). The far field dominates the Holtsmark nearest neighbour field at plasma conditions kT/e2n1/3 > 1.
Beiträge zur Untersuchung der Halbleitung in den Europiumsesquioxiden
Authors: Schwab Georg-Maria , Bohla Friedrich
Published: March 2015

Mit einer an hochohmigem Oxidmaterial bereits erprobten Apparatur erfolgte durch Gleichstrom-Spannungsmessung unter Luft oder kontrollierter Atmosphäre unterschiedlichen Druckes eine Messung der elektrischen Leitfähigkeit von polykristallinen Sinterkörpern aus kubischem oder monoklinem Europiumsesquioxid.

Bei hohen wie extrem niedrigen Sauerstoffpartialdrücken wurde an undotierten wie dotierten Oxidproben bei konstant gehaltenem Druck die Temperaturabhängigkeit bzw. bei konstant gehaltener Temperatur die Sauerstoffdruckabhängigkeit der Leitfähigkeit beobachtet.

Es wird versucht, ein Fehlordnungsmodell für den auftretenden Störstellenmechanismus zu geben.