bluuebunny/crossref_metadata_2025 huggingface dataset:
Optically Thin Hydrogen Plasma with Self-Consistent Electron Velocity Distribution
Authors: Oxenius J.
Published: February 2015

Occupation numbers of the atomic levels and degree of ionization of a stationary optically thin hydrogen plasma are calculated for temperatures in the range 8000 °K ≲ T ≲ 16000 °K and for electron densities in the range 109 cm-3 ≲ ne ≲ 1017 cm-3. The electron velocity distribution is not supposed to be Maxwellian, rather, it is obtained in a self-consistent way from the corresponding kinetic equation which is solved simultaneously with the equations that describe the statistical steady-state of the atomic levels. Besides spontaneous radiative bound-bound transitions and radiative recombinations, inelastic electron-atom collisions as well as elastic electronelectron and electron-atom collisions are taken into account. Hydrogen atoms are approximated by model atoms having four bound levels and a continuum. The numerical results show that for temperatures T ≲ 10000 °K the tail of the electron distribution function differs markedly from that of a Maxwell distribution, except in the case of high electron densities. Likewise, the selfconsistently calculated values of the atomic occupation numbers and of the degree of ionization there deviate strongly, up to several orders of magnitude, from those obtained by assuming a Maxwellian velocity distribution of the electrons.
Calculation of the Force Acting on an Impurity in a Metal Submitted to an Electric Field or a Temperature Gradient
Authors: Gerl Maurice
Published: February 2015

Using the Bosvieux-Friedel polarization model, the charge carrier induced force on an impurity in a normal metal submitted to a temperature gradient or an electric field is calculated, and a connection is made between the two phenomena. The results are interpreted in terms of the specific resistivity and thermoelectric power of the impurity in the matrix.

A crude estimation of the force due to phonon scattering on an impurity in a temperature gra­ dient is given
Elektron-eiektron-doppelresonanz mit hilfe einer neuartigen mikrowellen-briickcn-anordnung
Authors: Vieth H. M. , Brunner H. , Hausser K. H.
Published: February 2015

A new type of X-band microwave bridge is described. It consists of a cavity and a helix arranged in an orthogonal manner in order to obtain maximal decoupling.

A variable frequency double resonance spectrometer com­prising this arrangement is used to measure ELDOR of free radicals in solution
Nonresonant Diffusion of Particles in Stochastic Fields
Authors: Biskamp D. , Pfirsch D.
Published: February 2015

A Fokker-Planck equation for the non-resonant scattering of particles by general weakly turbulent electromagnetic fields is derived using a simple quantum-mechanical method. The equation is compared with the corresponding weak turbulence equation as given e. g. in Kadomtsev's book and two applications are discussed.
Konzentrationslöschung durch Energieübertragung bei der Lumineszenz von Lösungen
Authors: Bojarski C. , Kuśba J. , Obermüller G. , Oberm G
Published: February 2015

Die Absorptionsspektren und Quantenausbeuten der Fluoreszenz von Rhodamin 6 G werden in zwei verschiedenen Wasser-Glycerinmischungen in Abhängigkeit von der Rhodaminkonzentration untersucht. Die beobachtete Konzentrationslöschung wird auf die Bildung von Rhodamindimeren zurückgeführt und die Abnahme der Quantenausbeute mit theoretischen Vorstellungen über die Kon­zentrationslöschung durch Energieübertragung zu den Dimeren verglichen.
Diffusionsuntersuchung im System Pd—Ta mittels Mikrosonde
Authors: Brunsch A. , Steeb S.
Published: February 2015

Diffusion processes were investigated by means of quantitative electron-probe microanalysis in the system Pd-Ta. The annealing temperature amounted from 700 °C up to 1030 °C. In the diffusion zone the phases Pd2Ta, Pd3Ta, Pd15Ta4, Pd5Ta, Pd6Ta and Pd17Ta2 were observed. The phase diagram only shows the phases PdTa, Pd2Ta, and Pd3Ta. From the law d = k√t it can be concluded for the growing process of the total diffusion zone, that volume diffusion predominates within this system. The values of log k2 as well as the values of log D versus 1/T yield an Arrhenius plot. The corresponding values are given in tables for the total diffusion zone as well as for the single phases. The discussion of a scanning-picture shows greater diffusion velocity for the Palladium atoms than for the Tantalum atoms.
Correlation Factor for the Diffusion of Charged Impurities in the Diamond Structure
Authors: Mehrer H .
Published: February 2015

The correlation factor for impurity diffusion by a vacancy-mechanism is a function of the vacancy-jump frequencies in the surroundings of the diffusing atom. Since in Si and Ge the vacancy can act as an acceptor, a long-range Coulomb interaction between donor atoms and vacancies exists. The usual assumption, that only a few vacancy-jump frequencies in the immediate surroundings of the vacancy are different from the jump frequency in the pure matrix, is not justified in this case.

A very general expression for the correlation factor of impurity-diffusion in the diamond structure is deduced. Vacancy-jump frequencies for jumps which originate from first-, second-, and third-nearest neighbours are treated explicitely. For more remote jumps the Coulomb force is taken into account as a drift force operating on the migrating vacancy. After specializing the general expression it is compared with the well-known ,,four-frequency-model" of Manning.
Interaction of 14.0 MeV-Neutrons with 12C in Stilbene
Authors: Fabian H.-U.
Published: February 2015

The pulse height spectrum of all heavy charged particles induced by 14.0 MeV neutrons in a 1" × 1" stilbene scintilla­ tor was measured using a pulse shape discriminator and the associated particle technique. The proton pulse spectrum was subtracted and the remaining alpha-pulse distribution is shown in a diagram. The sum of the cross sections for the reactions 12C (n, n') 3 α and 12C (n, α)9 Be was determined to be σc= (260±20) mb.
The Dissociation Energy of the Molecule PdGe
Authors: Peeters R. , Auwera-Mahieu A.M. Vander , Drowart J .
Published: February 2015

The dissociation energy of the molecule PdGe w as determined by the mass spectrometric Knudsen cell method: D0
0 (PdGe) =256.6± 12 kJ mol-1 (61.4 ± 3 kcal mol-1) .
Absolute Spin Assignments of Dy161 and Dy163 Neutron Resonances and the Hyperfine Coupling Constants in Dy163
Authors: Brunhart G. , Postama Hans , Rorer D.C. , Sailor V.L. , Vanneste L.
Published: February 2015

A method and equipment are described for measuring the spin dependence of slow neutron cross sections. The neutron beam from the High Flux Beam Reactor (HFBR) is polarized by Bragg reflection from a magnetized 92% Co-8% Fe single crystal which process also serves to select the neutron energy. Nuclei in the target are statically polarized in a field of ∼ 35 kOe at temperatures ranging from 0.05 to 0.10 K. Large nuclear polarizations are obtained in polycrystalline ferromagnetic dysprosium metal because of the large magnetic hyperfine interaction. The total angular momenta, /, of the compound states corresponding to the first several resonances in Dy161 and Dy163 were determined by measuring the transmission of the target with the neutron beam alternately polarized parallel and antiparallel to the nuclear polarization. Quantitative results at two resonances of opposite spin permit absolute /-value assignments (i. e., the assignments are independent of any knowledge of the absolute signs of the nuclear magnetic moments).

Results were as follows:

Isotope 163 161 161 161 161 161 161 161 161 163 161 161

E0 (eV) 1.71 2.72 3.69 4.35 7.75 10.40 10.87 12.65 14.3 16.25 16.7 18.5

J 2 3 2 2 3 2 3 2 (?) 2 3 (?) 2

The hyperfine interaction constants for Dy163, obtained by measuring the nuclear polarization as a function of temperature, were A/k = 0.100 ± 0.005 K, and P/k = 0.008 ± 0.001 K where A and P are, respectively, the magnetic and the electric hyperfine interaction constants.
Nuclear Gamma Resonance Study of the Ir —Fe and Ir —Ni Alloy Systems
Authors: Mössbauer R.L. , Lengsfeld M. , Lieres W. Von , Potzel W. , Teschner T. , Wagner F. E. , Kaindl G.
Published: February 2015

The Ir-Fe and Ir-Ni alloy systems were studied over the whole composition range by means of the nuclear resonance absorption of the 73 keV y-rays of 193Jr and of the 14.4 keV y-rays of 57Fe. The magnetic hyperfine field at the Ir-nuclei in Ir-Ni alloys decreases approximately linearly with the Ir concentration from - 460 kOe at 4.2 K in very dilute alloys to zero at about 20 at.-% Ir. This behaviour is paralleled by the decrease of the magnetic moment per Ni atom as determined from bulk magnetization measurements. The hyperfine fields at both Ir and Fe were measured for the ferromagnetic bcc phase of the Ir-Fe system. They turned out to be virtually independent of concentration with values of about -1400 kOe and - 330 kOe, respectively. Linewidths increasing with the Ir concentration indicate a distribution of hyperfine fields. The fee phase of the Ir-Fe system has been found to be paramagnetic at 4.2 K throughout the range of its existence. The dependence of the hyperfine fields on concentration is discussed in terms of a rigid 3d-band model combined with local shielding. A discussion of the concentration dependence of the 193Ir and 57Fe isomer shifts has to take into account lattice expansion as well as band repopulation effects.
hcp-Argoneinkristalle: Zucht und Messung der Doppelbrechung
Authors: Hagele W. , Probst W. , Dellian K. , Hingsammer J. , Lüscher E.
Published: February 2015

A procedure for growing hcp argon single crystals doped with oxygen is described. The hcp crystal structure is confirmed by birefingence and neutron scattering experiments. The birefringence at 77 °K of a hcp argon single crystal doped with 2% oxygen is determined to be ne-n0 = + (2.11 ± 0.63) · 10-6. From this result one can calculate the Lorentz field factors, obtaining fo = (333 328.6 ± 1.4) · 10-6 and fe = (333 342.7 ± 2.8) · 10-8. Using Ewald's theory of structural birefringence to determine σ = c/a from the measured birefringence yields σ = (163 451 ± 3) · 10-5. This value definitely excludes the ideal hcp structure (σ = 1.63299), in contrast with the results of X-ray measurements.
Investigation on the Primary Spins of the 235U Fission Fragments
Authors: Armbruster P. , Labus H. , Reichelt K.
Published: February 2015

The prompt γ-radiation emitted in 235U thermal fission has been investigated in a multiparameter experiment, γ-yield, time-distribution, energy spectrum and nuclear anisotropy of the emission have been measured, especially γ-yield and anisotropy as a function of fragment mass and γ-energy. The mass dependence of the primary spins of the fragments can be deduced from these measurements. A value of 7 h̶ for the average primary spin and an increase of the primary spins within each fission product group is obtained. This dependence is explained within an adiabatic model of scission due to the mass dependence of the deformation of the fragments.
Electron Paramagnetic Resonance Study of Copper (II)-tetrammine Nitrate in Solution
Authors: Vierke G.
Published: February 2015

The electron paramagnetic resonance of copper (II)-tetrammine nitrate in solution of methanol and water has been investigated. The data obtained from the spectra at room temperature and 97 °K together with the optical transition energies determined from single crystal polarized absorption spectra at 77 °K by other authors were used to calculate the LCAO-MO bonding parameters. The bonding orbital of the ammonia molecule cannot be described by the concept of sp2 hybridization which was exclusively used in the theory. Therefore a calculation of the overlap integral S(n) for α bonding and of the superhyperfine splitting was carried out in terms of an arbitrary hybridization parametern. For ammonia, n was taken from the Duncan-Pople hybrid wave function for the lone pair orbital. The o bonding and the out-of-plane π bonding appear to have a moderate degree of covalency (α = Ϭ = 0.91; α’= 0.49). The covalent in-plane n bonding is somewhat stronger (β = 0.87) but is by no means so strongly covalent as is observed in compounds with ligands which do not exclusively coordinate through the lone pair electrons.

At low temperature nine ligand nuclear superhyperfine structure lines corresponding to the interaction of four magnetically equivalent nitrogen nuclei have been observed. The value of α' derived from the superhyperfine splitting is in excellent agreement with that obtained from the copper nucleus hyperfine structure.
Streumessungen am System LiCs und das Singulett-Potential dieses Moleküls / Total scattering Cross Section Measurements for LiCs and the Singlet Potential of this Molecule
Authors: Kanes H. , Pauly H. , Vletzke E.
Published: February 2015

The velocity dependence of the total collision cross section has been measured for the system LiCs in the energy range from 15-1000 eV. Using the observed glory undulation together with spectroscopic data a potential for the singlet ground state of LiCs is proposed.
Image Converter and Intensiner Investigations on Luminous Fronts (Ionizing Waves) in Nitrogen Discharges in a Homogeneous Field
Authors: Koppitz J.
Published: February 2015

In this paper optical space and time resolved measurements on the later development of Kanal (streamer) and Townsend discharges in nitrogen are treated. In both discharges fast luminous fronts (the so called ionizing waves) arise: in the streamer discharge between the primary streamer stage and the spark stage, and in the Townsend discharge during the transition to the glow.

For the streamer discharge new experimental results are given, especially at high overvoltages. In the case of the Townsend discharge the development of an idealized, nearly one dimensional dis­charge is treated. The experimental results are in good agreement with theoretical considerations. In contrast to this idealized discharge often strong constrictions are found during the development to the glow, so that the discharge becomes nearly filamentary. The reasons for this behaviour are discussed and the way to avoid it.
Notizen:Ein Experiment zur retrograden Bewegung von Lichtbögen
Authors: Bartels Klaus
Published: February 2015

Eine elektrische Bogenentladung bewegt sich in einem transversalen magnetischen Feld senkrecht zu diesem Feld und zur Stromrichtung. Im allgemeinen erfolgt diese Bewegung im Sinne der Ampereschen Re­ gel, bei niedrigem Druck jedoch kann sich der Bogen in entgegengesetzter, "retrograder" Richtung bewegen. Zur Deutung dieser retrograden Bewegung eines freibrennenden Lichtbogens wurde eine Reihe von Hy-* Sonderdruckanforderungen an Seminar für Didaktik der Physik, Pädagogische Hochschule Ruhr, Abteilung Essen, D -4300 Essen, Henri-Dunant-Straße 65. 1 Eine Übersicht findet man in A. E i d i n g e r u . W. R i e d e r , Arch. Elektrotechnik 43, 94 [1957].
Notizen:Allgemeine Aussagen über Aktivitätskoeffizienten bei Elektrolytschmelzen
Authors: Haase R.
Published: February 2015

Wir betrachten eine flüssige Mischung, die aus zwei Elektrolyten mit je zwei Ionenarten besteht. Dabei soll eine Ionenart den beiden Elektrolyten gemeinsam sein. Reispiele stellen die Salzschmelzen N aN 03-f AgNOs und PbCl2 + PbBr2 dar. An Hand dieses relativ ein­ fachen Typs von binären Elektrolytschmelzen, der schon vor kurzem1 hinsichtlich der Transporteigenschaften untersucht worden ist, sollen einige thermodynamische Gesetzmäßigkeiten abgeleitet und diskutiert werden. Diese betreffen die Abhängigkeit der Aktivitätskoeffi­ zienten von der Zusammensetzung sowie die Beziehun­ gen zwisdien den Aktivitätskoeffizienten der einzelnen Teilchenarten und denen der Komponenten. Obwohl man heute, auch bei der Thermodynamik der Elektro­ lytschmelzen, in zunehmendem Maße zur Beschreibung durch "Zusatzfunktionen" übergeht2, ist das hier zu besprechende Problem in Zusammenhang mit einer all­ gemeinen Formulierung der Grenzgesetze für unend­ liche Verdünnung wichtig. Molekularstatistisch sind ja die primären Einheiten nicht die Komponenten oder ionischen Bestandteile, sondern die wirklich vorhande­ nen Teilchenarten. Die beiden Elektrolyte der binären Schmelze werden als Komponente 1 und Komponente 2 bezeichnet. Die­ jenige Ionenart, die nur in der Komponente 1 bzw. 2 vorkommt, wird Teilchenart a bzw. b genannt. Die den beiden Komponenten gemeinsame Ionensorte heißt Teil­ chenart c. Die Zahl der Ionen der Sorte a bzw. b, die aus einem Molekül der Komponente 1 bzw. 2 bei der Dissoziation hervorgehen, wird mit r a bzw. vb bezeich­ net, während das Symbol vc bzw. vc' die Zahl der Ionen der Sorte c bedeutet, die aus einem Molekül der Kom­ ponente 1 bzw. 2 stammen. So gilt etwa für die Salz­ schmelze N aC l(l) +M gC l2(2) : n = ^Na+ = 1,
Notizen:Anisotropie der 195Pt-KMR-Verschiebungen kristalliner Platin(II)-Verbindungen
Authors: Keller H. J. , Rupp H. H.
Published: February 2015

Wie wir bereits kürzlich am Beispiel des kristallinen K2PtCl4 zeigen konnten1, tritt bei quadratisch koordi­nierten Platinkomplexen eine Anisotropie der chemi­schen Verschiebung des 195Pt-KMR-Signals in der Grö­ßenordnung von 1% auf. Um den Einfluß von im Sinne der "spektroskopischen Reihe" verschieden starken Li­ganden auf die magnetische Anisotropie zu überprüfen, haben wir nun zusätzlich Kristalle der Verbindungen (2) - (4) der Tab. 1 untersucht.
Fluorescence Investigations on Intramolecular Energy Transfer in Alkyl-Fluorenole and Alkyl-Anthracene
Authors: Fick E. , Herler H. , Heusinger H.
Published: February 2015

Fluorescence investigations of alkyl fluorenole- and alkyl anthracene-solutions in n-hexane or cyclohexane resp. were performed for β- and UV-excitation. The observed influence of scavengers for electrons or positive ions on the fluorescence intensity for β-excitation reveals that charge trans­fer is the predominant process for the intermolecular energy transfer from solvent to solute.

The fluorescence intensity of alkyl fluorenoles and alkyl anthracenes increases with increasing number n of CH2-groups in the alkyl chain, reaching a plateau for n ~ 6. This gives evidence for intramolecular energy transfer within the CH2-Chain with a limited range. Using a simple model in alkyl fluorenoles for the transfer probability from Cn to Cn-i in the chain a value of 0.65 could be deduced. The model derived for n-alkyl fluorenoles fits to the values of branched alkyl fluorenoles as well.

The results obtained from the fluorescence measurements are compared with those on C - H- bond breakage in the aliphatic chain, derived from investigations of hydrogen production and ra­dical formation. Possible mechanisms for intramolecular energy transfer are discussed.
Einfluß von Fehlstellen und Verunreinigungen auf den Ordnungs-Unordnungs-Übergang im hexagonalen Eis Ih
Authors: Sesselmann I. , Helmreich D.
Published: February 2015

Die Temperaturabhängigkeit der longitudinalen elastischen Konstanten c33 von reinem und c33HF von HF-dotiertem schweren Eis wurde im Bereich zwischen 80 und 200 °K mit einer Phasenvergleichstechnik gemessen. Beim HF-dotierten D2O-Eis wurde unterhalb 150 °K eine positive Anomalie gefunden. Reines D2O-Eis verhält sich im gemessenen Temperaturbereich normal.

Die Ergebnisse können erklärt werden durch mikroskopische, im Hochtemperaturbereich stabile Keime der Tieftemperaturphase, die beim Abkühlen Zentren der neuen Phase werden.
The Specific Heat of Pure and Doped Ice Near 120 °K
Authors: Pick M. A. , Wenzl H. , Engelhardt H.
Published: February 2015

. The specific heat of pure and doped ice Ih single crystals was measured from 80°K to 230 °K with a differential heat-fiux calorimeter. In the region near 120 °K the specific heat exhibits a positive anomaly which is explained by a partial ordering of the ice.
Thermally Stimulated Currents in the Range of Unity Gain Factor
Authors: Bragagnolo J. A. , Dussel G. , Böer K. W. , Dussel G. A.
Published: February 2015

Thermally stimulated current-curves in CdS platelets with slit electrodes change their character when the photoelectric gain-factor increases above one. Here the photocurrent remains essentially frozen-in up to temperatures at which marked thermal quenching sets in. A positive space charge region is assumed to be responsible for the frozen-in photocurrent. A reliable TSC-analysis of the trap distribution can be conducted only for gain factors considerably below one.
The Concept of Reversibility and Irreversibility in Thermostatics
Authors: Schröter Joachim
Published: February 2015

First a general definition of reversibility is given which is in accordance with the mechanical concept of reversibility. This definition is applied to thermostatics. It is shown that the smooth curves in the space of equilibrium parameters can be approximated arbitrarily by irreversible or by almost reversible real processes. The work done during an almost reversible process is given by a Pfaffian form. The converse is also true. If the differential work is given by a Pfaffian form the processes are practically reversible. Finally the uniqueness of a Pfaffian form is shown, if it is used as differential work.
Impedances of Warm Plasmas near the Lower Hybrid Resonance
Authors: Babu R. , Schlüter H.
Published: February 2015

With full electromagnetic treatment electron pressure effects are included in the calculation of plasma impedances and power transfer to a plasma cylinder in the domain of the lower hybrid resonance. The general results are applied to cases of interest in radio frequency discharges with azimuthally symmetric excitation and zero coil-plasma-gap. For these specific situations the effects of electron pressure are found to be small.
Thermodynamik heterogener Gasgleichgewichte II. Gasphasenzusammensetzung und chemische Transportreaktionen in den Systemen Wolfram — Halogen (Fluor, Chlor, Brom)
Authors: Neumann G. M. , Gotschalk G.
Published: February 2015

Zur Beurteilung der Frage nach der Möglichkeit und der Richtung eines chemischen Transportes von Wolfram in den Wolfram-Halogen Systemen bei Vorliegen eines Temperaturgradienten werden die Gleichgewichtszusammensetzungen der Heterogensysteme berechnet. Die Berechnungen werden mit Hilfe von Computerprogrammen für die mit Wolfram als Festkörper koexistierende Gasphase für Temperaturen von 500-bis 3600 °K und für Halogen-Anfangsdrucke von 1 -10-6 atm durchgeführt.

Aus der Temperaturabhängigkeit der Massenbilanz des Wolframs ergibt sich die prinzipielle Möglichkeit von Transportreaktionen in diesen Systemen. Von besonderem Interesse ist die Umkehr der Transportrichtung, die für die einzelnen Wolfram-Halogen Systeme charakteristisch ist.

Die Ergebnisse der Berechnungen werden durch experimentelle Beobachtungen bestätigt.
Notizen: Chemische Reaktionskinematik. XV. Winkel- und Geschwindigkeitsverteilung des Produkt-Ions der Reaktion Kr+D2->+D2→KrD+ +D
Authors: Henglein A. , Bosse G. , Ding A.
Published: February 2015

The cross section of the reaction Kr++D2→KrD++D is about 10 times smaller than that of the corresponding reaction between Ar+ and D2 . The KrD+ ion is nearly isotropically scattered (cm-system) at a relative translational energy of 0.89 eV. At 2,70 eV, maximum KrD+ intensity is found at the velocity expected from the spectator stripping model, although significant isotropic scattering still occurs. The interaction of he incident ion with the spectator D-atom is much stronger for Kr+ than for Ar+. It is proposed that rather eccentric colisions lead to stripping, while rather centric collisions lead to hard sphere scattering of the product ion.
The Use of the Modified Extended Hiickel Method in the Dynamics of Molecules Containing Multiple Bonds
Authors: Yeranos Walter A.
Published: February 2015

Using the acetylene, ethylene and ethane series, the applicability of the Modified Extended Hiickel Method in the determination of the atomization energies as well as stable configurations of molecules has been demonstrated. It is believed, moreover, that within the procedual framework of our proposed technique the proportionality constants Fσ (HH) =2.00, Fσ (CH) =1.75, Fσ (CC) = 2.10 and Fπ (CC)=1.45 should prove adequate in the semi-empirical study of the atomization energies, stable configurations (and potential barriers) of all the hydrocarbons, be they aliphatic or aromatic.
MOS-Sandwich-Gitter-Diode zur Erzeugung von Feldionisationsfeidstärken an der Phasengrenze Festkörper/Gas
Authors: Gentsch H. , Prüller H.
Published: February 2015

The sandwich grid diode is a new means of producing extremly high elektrical fields at a solid surface. The ability to ionize gases and to produce field electrons with such a thin film system permits an estimate of the maximal field strength. It is interesting to note, that with this diode one can produce fields higher than 5-107 V/cm in gases up to atmospheric pressure without the risk of a discharge. This fact may become of some importance for the study of field induced desorption and catalysis.
Aktivitätskoeffizienten bei Salzschmelzen mit drei Komponenten
Authors: Richter Joachim
Published: February 2015

The activity coefficients of molten salts with three components will be defined, and the logarithms of these activity coefficients will be represented as power series in the mole fractions of the two other components with integral exponents. Power series with three empirical parameters have proved useful as first approach for low molecular nonelectrolyte solutions, and they also describe the activity coefficients of a ternary melt adequately. In the appendix a general formula will be given for the activity coefficients of a melt composed arbitrarily containing water as an additional com­ponent.
Zur Verbreiterung der Wasserstoff-Linie Ly-a durch starke Elektronenstöße
Authors: Pfennig H.
Published: February 2015

A study of how strong electron collisions will influence the profile of the line core is made with­ in the framework of the impact theory. To this end the time-dependent Schrödinger-equation describing the change of state of the atom during the passage of one perturbing electron is solved numerically down to impact parameters equal to the de Broglie-wavelength 2 . In this range the classical description of the perturbing electrons is assumed to be still valid. In the dipole-only case the solution can be expressed exactly by elementary functions. The line profile clearly shows how important it is to consider the strong collisions. All the different ways of doing this lead to nearly the same results.
Die Tem peraturabhängigkeit des Soret-Koeffizienten von n-Octan — Benzol
Authors: Korsching H.
Published: February 2015

The temperature dependence of the Soret effect is measured by an optical method. A special slit cell is used with the slit plane parallel to the direction of the temperature gradient.
A Nonenergetic Theory of Heat
Authors: Job G.
Published: February 2015

The current interpretation of heat is completely different from the earlier concept which was quite successful at the beginning. Then, it was thought that heat was a quantity which could be neither created nor destroyed and that it was present in every material body. A body should become hotter by absorption of heat and expand, melt, vaporize or decompose, if the temperature necessary for these processes is reached1-5. On this basis, Black explained the existence of latent heats3, Carnot calculated the effective work of ideal heat engines4, Clapeyron found the connection between vapor pressure and heat of vaporization 6 and Thomsen developed the first material-independent definition of temperature 7. In spite of their success, these interpretations were in opposition to several experimental results showing that heat was obviously produced by consumption of work. These facts indicated a relationship between the two quantities.
Experimental Evidence of Fine Structure in Channeling Lines
Authors: Lutz H. O . , Ambros R. , Mayer-Böricke C. , Reichelt K. , Rogge M.
Published: February 2015

Fine structure was found in the angular distribution of 2 MeV He ions channeled between the (001) planes of 1600 to 3000 Å thick Au single crystals. In addition, the energy loss of the channeled particles was determined as a function of exit angle from the crystal.
Streuung von Ionen I. Regenbogeneffekt bei der elastischen Streuung von Protonen an Argon
Authors: Mittmann H.-U. , Weise H.-P. , Ding A. , Henglein A.
Published: February 2015

A crossed beam apparatus for scattering experiments with ions on atoms or molecules is described. The results for the elastic scattering of H+ on Ar are reported. Both the structure of the secondary rainbows and the superimposed fine structure were resolved. In order to fit the experimental curves, differential cross sections were calculated in WKB approximation using the following reduced potentials:

n, m, g1, g2 , g3 , L, G1 and G2 are form parameters for adjusting the width of the potential well. The fitting procedure and the influence of the chosen potentials on the resulting potential depth E and the equilibrium distance rm are described. Further, the information which can generally be obtained from the observed rainbows and the superimposed fine structure are discussed. No combination of n, m, rm and ε yielded a differential cross section in agreement with the experiments, if the Lennard-Jones potential ULJ or the modifications of Mason and Vanderslice or Schlier and coworkers are used, but excellent agreement can be obtained with the above expressions for U1 and U2 using suitable parameters. For the system H+-Ar we obtain ε = (4.04+0.1) eV, rm = (1.31±0.07) Å. These values are in good agreement with recent ab-initio calculations of Roach and Kuntz. They are considerably different from those obtained by Champion et al. 8, who did not observe the fine structure and used a too narrow potential in the evaluation of the scattering data.
Experimente zur elastischen Streuung von Kaliumatomen (2S1/2) an Jodatomen (2P3/2) in gekreuzten Molekularstrahlen
Authors: Hack W. , Rosenkranz F. , Wagner H. Gg.
Published: February 2015

Der differentielle und totale Streuquerschnitt von 2S1/2 Kaliumatomen an 2P3/2 Jodatomen wurde in gekreuzten Molekularstrahlen bei thermischen Relativenergien gemessen. Im Bereich von Ablenkwinkeln δ < 2° wurden Maxima des differentiellen Streuquerschnittes gefunden, die sich über die klassische Regenbogenstreuung deuten lassen.

Messungen des totalen Streuquerschnittes bei Relativgeschwindigkeiten von 0,5 bis 1,8-105 cm/sec zeigen eine Abhängigkeit von der Geschwindigkeit, wie sie für die van der Waals Anziehung charakteristisch ist. Für höhere Relativgeschwindigkeiten wurden Abweichungen beobachtet, die sich dadurch deuten lassen, daß die Streuung am abstoßenden Teil der Wechselwirkungspotentiale den Verlauf des totalen Streuquerschnittes maßgeblich beeinflußt. Für die Potentialtöpfe der angeregten kovalenten Elektronenzustände des KJ ergibt sich mit dieser Deutung

εΩ= 1 ≈3,3 · 10-3 eV,

εΩ= 0+, 0-, 2 ≈ 2,5 · 10-3 eV.

εΩ= 0+, 0-, 2 ≈ 1,9 · 10-3 eV.
Force Field Study of Some Hexahalide Anions of Transition Metals
Authors: Avasthi M. N. , Mehta M. L .
Published: February 2015

Using the L matrix approximation method of Müller the seven independent force constants for the hexahalide anions of zirconium and hafnium metals have been evaluated employing general valence force field (GVFF). The stretching force constant increases as the oxidation number of the metal increases. The mean amplitudes of vibration have been calculated using the L matrix approximation method. The trends of mean amplitudes of vibration have also been discussed.
Normal Coordinate Analysis of Some Hexahalide Anions of IV Group Elements
Authors: Avasthi M. N. , Mehta M. L.
Published: February 2015

The normal coordinate analysis has been applied to the hexachloride and hexabromide of tin, titanium, zirconium and hafnium, using the Urey-Bradley force field (UBFF) and orbital valence force field (OVFF). It is observed that the stretching force constant increases as the oxidation number of the metal increases within isoelectronic series.
Barium Exhaust Spectrum during the Expansion of Combustion Products through a Nozzle into Vacuum
Authors: Batalli-Cosmovici Cristiano , Michel Karl-Wolfgang
Published: February 2015

The emission spectrum from a two-phase nozzle jet, consisting of combustion products of Ba and CuO, revealed that non-equilibrium amounts of excited and ionized Ba atoms occur only during the nozzle starting transient.

Traces of BaO-and Cu2-molecules could be identified in the cold outer parts of the jet. The particle temperature near the nozzle, derived from novel measurements of apparent color and brightness temperature, confirms LTE calculations if the vaporization of excess Ba is taken to be a fast process.
Durch Bestrahlung mit Röntgen-Licht bei LNT und Zimmertemperatur verfärbtes Ammoniumjodid
Authors: Podszus B.
Published: February 2015

FR-centers have been produced by x irradiation of ammonium iodide at liquid nitrogen temperature and have been studied by reflection-and luminecence-measurements. Pulse annealing experiments showed, that the J2~-centers were unstable above ~ 100 °K.

The 3,3 eV absorption band, first found by KAMIYOSHI5 , has been investigated by means of reflection measurements.
Some Remarks on the Gaussian Basis Functions. Application to Methylammonium
Authors: Hartman A.
Published: February 2015

The present work is an attempt to find a way for obtaining both relatively good total molecular energies and calculated molecular geometries, by using a relatively small basis set of Gaussian functions. It was found that if such functions are located in the middle of the bonds too, this goal can be achieved.
Defects in Neutron-irradiated ZnO (I)
Authors: Leutwein K. , Schneider J.
Published: February 2015

After irradiation with fast neutrons, several paramagnetic centers have been observed in ZnO by ESR. They result from electrons trapped at oxygen vacancies and from holes trapped at more complex defect associates.
Stationäre Bereiche der Plasmadiode
Authors: Goetz Hans-Peter , Müller Karl Gerhard
Published: February 2015

The plane collisionless plasma diode between two hot emitters is investigated. Only potential distributions with not more than one extremum are considered. The condition E2> 0 is taken into account. Thus nonphysical solutions as given by other authors are excluded. As independent parameters the diode voltage and the neutral gas current on the emitters are introduced. In diagrams the type of potential distribution and the potential extremum are shown. Regions occur with several solutions or no solution of the Poisson equation. These regions are increased by a difference between the emitter temperatures and are decreased by a trapping of charge carriers near the potential extremum
Die Wärmeleitfähigkeiten von reinem Ortho-und Para-Deuteriumgas und ihren Gemischen bei 18,4, 19,6 und 21,0 K / The Thermal Conductivities of Pure Ortho and Pure Para Deuterium Gas and Their Mixtures at 18.4, 19.6 and 21.0 K
Authors: Uebelhack W. , Eichenauer W. , Heinzinger K. , Klemm A.
Published: February 2015

The results of measurements at three temperatures on gases in the whole concentration range from pure o-D2 to pure p-D2 are presented in the form (γp the molar fraction of p-D2)

X/X (rp=0) = 1 - ki yp-.k2 yp2,

with ^ = 2 . 1 7 , 2.43, 2.97 - l O " 3 and A:2=2.37, 2.27, 2.24 - l O " 3 for 7 = 18.4, 19.6, 21.0 K respectively. From these coefficients, and making use of the Eucken relation, the ratios of the collision cross sections have been estimated to be

Ωpp/Ωoo = 1 + (4.37 ± 0.05) • 10-3,

Ωop/Ωoo = 1 + (1-05 ± 0.05) • 1O-3.

A temperature dependence of these ratios was not detected
Elektrische Transportgrößen von Bt100-x Sbx-Legierangen (x ≤ 40%)
Authors: Neisecke J. , Schneider G.
Published: February 2015

Durch Zonenschmelzen wurden einkristalline Bi100-xSbx-Legierungen im halbleitenden Bereich (5 ≦ x ≦ 40) mit 5, 10, 25 bzw. 40 At.-% Sb hergestellt, und zwar undotiert sowie mit Zusätzen des Donators Tellur bzw. des Akzeptors Sn. Die elektrischen Transportgrößen (elektrische Leitfähigkeit, magnetische Widerstandsänderung, Thermokraft, longitudinaler und transversaler Nernst- Ettingshausen-Effekt) wurden gemessen im Temperaturbereich von 80 °K bis Zimmertemperatur. Diese Eigenschaften in Abhängigkeit von Dotierung, Temperatur, Probenzusammensetzung und Magnetfeld wurden diskutiert. Werte für die Ladungsträgerkonzentrationen und Beweglichkeiten wurden berechnet
Die Molekülstraktur des Difluoramin-Schwefelpentafluorids SF5NF2
Authors: Haase J. , Oberhammer H. , Zentrum W. Zeil , Glemser O. , Mews R.
Published: February 2015

Die Molekülstruktur des Difluoramin-Schwefelpentafluorids in der Gasphase wurde mit Hilfe der Elektronenbeugung bestimmt. Verschiedene Möglichkeiten der Abweichungen der Bindungswinkel am Schwefel von 90° bzw. 180° wurden untersucht. Es zeigte sich, daß diese Abweichungen innerhalb der Fehlergrenzen vernachlässigt werden können. Die Ergebnisse für die verschiedenen Modelle sind in Tab. 1 zusammengestellt
Die Konfiguration organischer Radikale
Authors: Shanshal Muthana
Published: February 2015

Die Konfiguration am trivalenten Kohlenstoffatom (Radikalzentrum) organischer Radikale wurde anhand der MINDO/1-SCF-MO Methode und der 1/2 Elektron Approximation von DEWAR et al. studiert. Es zeigte sich in Ubereinstimmung mit den ESR-Untersuchungen, daß nicht alle Radikale eine planare Konfiguration besitzen. Die nichtplanare Konfiguration ist vor allem bei den cyclischen Radikalen mit kleineren, gespannten Ringen zu treffen. Beim Allyl-Radikal zeigte die Deformation des mittleren Protons eine Abhängigkeit vom C-C-C Valanz-Winkel.

Es wurde festgestellt, daß die MINDO/2 Methode keine genaue Aussage über diese Konfiguration erlaubt. Lediglich die Bindungsabstände mancher cyclischer Radikale (mit planearer Konfiguration) sind minimisiert worden. Bei den C5H5 und C3H3 Radikalen wird in Übereinstimmung mit früheren theoretischen Arbeiten eine Jahn-Teller Deformation zu Gunsten der weniger symmetrischen Struktur (Cs) festgestellt
Individual and Collective Aspects of the Microfield Distribution
Authors: H. Günter , Fischer Klaus G.
Published: February 2015

Starting from the exact formulation of the electric microfield distribution in an electron gas the question is investigated of whether collective phenomena are correctly included in previous calculations. Application of Böhm and Pines' procedure yields a separable expression for the total microfield distribution: the collective component is represented by a Gaussian distribution, the individual component is similar to the high-frequency profile of Baranger and Mozer. Both components vary with the cut-off parameter of the spectrum of the collective modes. For realistic values of this cut-off parameter the total distribution may differ from the high-frequency profile as much as ten per cent for systems close to the critical density. With increasing plasma parameter Λ the distribution approaches that of Holtsmark
Die physikalischen Grundlagen der Uran235 -Anreicherung nach dem Trenndüsenverfahren Die Wirkung des leichten Zusatzgases / Die Wirkung des leichten Zusatzgases
Authors: Becker E . W .
Published: February 2015

The Separation nozzle process for enrichment of U235 is based on the mass-dependent centrifugal force generated in a curved flow of a UF6/He or UF6/H2 mixture. It is shown that the experimentally determined separation effects can exceed those calculated for equilibrium separation in a stream flowing with an infinite velocity. A numerical analysis of the ternary diffusion process indicates that the separation of the UF6 isotopes is improved by the fact that the added light gas prevents the UF6 from concentrating rapidly at the boundary of the centrifugal field.
73 Ge Nuclear Magnetic Resonance Studies
Authors: Kaufmann J . , Sahm W.
Published: February 2015

The 73Ge spectra of some germanium-tetra-halides, germanium-tetra-alkyles, and of germanium-tetra-methoxide have been observed. The chemical shifts of these 73Ge NMR-lines were measured as functions of the temperature in the range up to 50 °C. In CS2-and benzene-solutions of Gel4 , two 73Ge-lines were found. The 73Ge NMR-spectrum of Ge(CH3)4 caused by indirect spin-spin-coupling between the 73Ge nucleus and the protons is well resolved. The spin-spin-coupling constants of Ge(CH3)4 and of Ge(OCH3)4, which shows an unresolved spectrum, were evaluated by an iterative least square fitting routine. The relaxation times T2 (in the range 30...740 msec) measured by the Carr-Purcell spin-echo-technique and calculated from the line widths are in good agreement. Precision measurements of the ratios of the Larmor frequencies of 73Ge in GeCl4, 41K in aqueous KF-solution and 2H in pure heavy water lead to a magnetic moment of 73Ge: μ = -(0.876 78 ± 0.000 01) μN (uncorrected).
Granulationsfreie Rekonstruktion von Hologrammen
Authors: Barlai P.
Published: February 2015

Described is a method for holographic reconstruction of diffusely illuminated objects which suppresses the known effect of granularity. The experimental setup is modest. It consists of a source of polychromatic light. Additionally there are inserted a simple ground glass and a diffraction grating in the reconstruction wave. Holographic reconstruction without granularity is achieved by incoherent superposition of longitudinal modes of the reconstruction wave.
Messung der Diffusion und des Isotopieeffektes von Silber in Blei
Authors: Herzig Chr. , Heumann Th.
Published: February 2015

Zur Klärung des Diffusionsmechanismus wurde die Diffusion und der Isotopieeffekt von Silber in Blei untersucht. Die gemessenen Diffusionskoeffizienten stimmen sehr gut mit den Werten anderer Autoren überein.

Der Isotopieeffekt von Ag105 und Ag111 in Blei wurde nach dem üblichen Schichtentrennungsverfahren bestimmt. Die Trennung der Impulsraten der beiden Isotope erfolgte einmal auf Grund ihrer unterschiedlichen Halbwertszeit und zum anderen auf Grund ihrer unterschiedlichen Zerfalls-eigenschaften (β-γ-Trennung).

Für den Isotopieeffekt wurde der Wert E ≌ 1 ermittelt. Dieses Ergebnis zeigt, daß die Diffusion von Ag in Pb im wesentlichen über Zwischengitterplätze abläuft.
Berechnung des Acetylenmoleküls
Authors: Egey Thomas
Published: February 2015

Es wird die Energie des Azetylenmoleküls im Grundzustand nach der VB-Methode berechnet. Die Elektronenfunktionen sind Slaterfunktionen mit Parametern, die sich aus Variationsansätzen für die Atome ergeben. Es werden nur homöopolare Zustände berücksichtigt. Betrachtet werden 3 1Σg
+- Zustände und deren Überlagerungszustand.
Zur Fein-und Hyperfeinstruktur von Lu I
Authors: Göbel L. H.
Published: February 2015

By means of the levelcrossing method the hyperfine structure constants and the lifetime as well as the angular momentum of the term 29607.98 cm-1 of LuI were determined. This term can be assigned to the 6s 27p 2P3/2-state. The signs of the interaction constants were obtained by the investigation of the line 3376.5 Å from this state into the 5d6s2
2D3/2 ground state in a Fabry-Perot interferometer. Together with the measured branching ratio from the lifetime the oscillator strengths were found. The results are:

J = 3/2;

B/| A | = 0.4947 (4); τ = 0.512 (16) · 10-8 (1.24/gJ) s;

A = 678.94 (2) gJ/1.24 MHz; f(3376.5 Å) = 0.382 (15);

B = 335.9 (3) gJ/1.24 MHz; f(3620.3 Å) = 0.15 (4) · 10-2.
Rotational and Vibrational Excitation of H2 by Slow Electron Impact
Authors: Linder F. , Schmidt H.
Published: February 2015

In a beam experiment the processes of elastic scattering, pure rotational excitation and deexcitation, pure vibrational excitation, and simultaneous rotational-vibrational excitation have been investigated for e-H2 scattering in the energy range from 0.3 eV to about 15 eV. Differential and integral cross sections have been determined in arbitrary units and calibrated on an absolute scale by normalization to absolute total cross sections. The results are discussed in terms of super-position of direct scattering, shape resonance and Feshbach resonance scattering and are compared with recent theoretical investigations. The cross sections for rotational and vibrational excitation, which are generally small for direct scattering, are greatly enhanced by a broad shape resonance near 3 eV and by Feshbach resonances around 12 eV. Characteristic differences in the excitation mechanisms are discussed.
Interaction of Randomly Phased Vibrational Waves via the Collision Dominated Solid State Plasma
Authors: Wonneberger W.
Published: February 2015

A diagrammatic technic is presented which is appropriate to study the nonlinear response of the collision dominated solid state plasma to randomly phased ac fields. By summation of diagrams, a nonlinear integral equation is established for the propagator S′ which is directly related to the nonlinear response function. Using the equation for S′, an equivalence is derived between a model solution in the theory of nonlinear coherent ultrasound amplification and the interaction theory of a great number of randomly phased vibrational modes, confined to a small frequency band.
Vibration-Rotation Interaction in the HF Molecule
Authors: Topouzkhanian Ara H. , Topouzkhanian Ari S.
Published: February 2015

The contribution of the vibration-rotation interaction term to the potential results in the fact that each rotational level has a slightly different potential curve. These deformed curves are used to integrate the Schrödinger equation.
Broadening of the Fine-Structure Raman Lines in Gaseous Oxygen
Authors: Hess S. , Knaap H. F. P.
Published: February 2015

Due to the coupling between the rotational angular momentum and the electronic spin, the depolarized Rayleigh light scattered from gaseous oxygen shows Stokes and anti-Stokes satellites shifted by about 60 GHz. The broadening of these fine-structure Raman lines is investigated theoretically for high and medium pressures where the linewidth is determined by two contributions, one proportional and the other inversely proportional to the pressure, p. The linewidth in the pressure broadening region is given by a relaxation frequency which is obtained from the Waldmann-Snider collision term. The p-1 contribution to the linewidth is determined by the ratio of the second moment of the fine-structure freqencies (with respect to the center of the shifted line) and another relaxation frequency. Both relaxation frequencies are sensitive to the nonspherical part of the inter-molecular potential.
Lokale Feldkorrekturen zum Elektron-Phonon-Matrixelement mit einer Anwendung auf den elektrischen Widerstand von Natrium im Bereich tiefer Temperaturen
Authors: Rauh A. , Bross H.
Published: February 2015

The electron-phonon-interaction is investigated within the RPA-scheme taking into account the local field of the crystal. In order to describe the screening by the conduction electrons an integral equation is solved in the limit of long phonon-wavelength. In contrast to the usual procedure, which is based on the deformation potential, the form factor of the ion potential and the electron wavefunction are needed in the present calculation. In the case of sodium the latter are calculated by the OPW method. Neglecting virtual interband transitions the T 5 -coefficient is found to be enlarged by 30% due to the local field. The result cannot explain the existing discrepancy of a factor 3 between experimental and theoretical resistivity.
Elastische und thermoelastische Konstanten des monoklinen Zinndifluorids
Authors: Acker E. , Recker K. , Haussühl S. , Siegert H.
Published: February 2015

All elastic and thermoelastic constants and the coefficients of thermal expansion of monoclinic SnF2 are measured. These properties deviate strongly from the behaviour of other difluorides such as CaF2 and MgF2. The high anisotropy, the large bulk compressibility and the departures from the Cauchy relations suggest the existence of strong covalent binding components between tin and fluorine atoms. The thermal properties are in accordance with Grünseisen's rule.