bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Turbulence by the Interaction of Gas Flow with Plasmas
Authors: Niemeyer Lutz , Ragaller Klaus
Published: February 2015

A high current electric arc in the axis of a supersonic nozzle flow is studied experimentally and theoretically in order to clarify the physical nature of light emission fluctuations which are observed inside the nozzle. The gas flow is produced by discharging a high pressure reservoir of 20 at N2 through a nozzle of 12 mm throat diameter. The arc is fed with a rectangular current pulse of 1.9 kA amplitude and 5 ms duration. The light emission fluctuations of the arc are observed by photographic and photoelectric methods. The results of the observations are compared to theoretical estimates and lead to the conclusion that the fluctuations are caused by hydrodynamic turbulence. This turbulence is shown to be generated by the combined occurrence of a strong axial pressure gradient and a strong radial density gradient in the boundary layer between the arc and the surrounding cold gas flow. The influence of specific plasma properties on the character of the turbulence is briefly discussed from a theoretical point of view.
Natrium-23 und Lithium-7 NMR-Untersuchungen an Silicat- und Boratgläsern / 23Na and 7Li NMR Studies of Silicate and Borate Glasses
Authors: Krämer F. , Müller-Warmuth W. , Scheerer J.
Published: February 2015

The 23Na and the 7Li NMR spectra from several binary- and ternary alkali silicate and alkali borate glasses have been examined as a function of composition and temperature. At temperatures well below room temperature both the magnetic dipolar interactions between various nuclei and the electric quadrupolar interactions with the surroundings remain more or less the same in all the glasses. Upon increasing the temperature the width of the central transition of the 7Li absorption decreases, the 23Na dispersion changes from a quadrupolar to a more dipolar like shape, and important spin lattice relaxation is produced. Substitution of other alkali ions for lithium and sodium, respectively, affect the dynamic rather than the static behaviour of the glasses. The results are discussed with the assumption that the main contribution to the NMR signal is from nuclei belonging to alkali-rich regions which look similar in silicate and borate glasses, and for different alkali ions. The phenomena of motional narrowing, temperature dependent relaxation and drastic change of dispersion spectra are attributed to the diffusion of the alkali cations. From the relaxation data activation energies between 14 and 22 kcal/Mol have been obtained. Particular attention has been paid to the mixed alkali effect.
gJ-Faktor der Molekeln SnO und PbO und Anisotropie ihrer magnetischen Suszeptibilität / Molecular gJ-Factor and Magnetic Susceptibility Anisotropy of SnO and PbO
Authors: Honerjäger R. , Tischer R.
Published: February 2015

The gJ-factor and the magnetic susceptibility anisotropy ξT have been measured for 120Sn18O and 208Pb16O in the vibrational state υ=0:

120Sn16O gJ= -0,14631 (38), ξT/h = 1844(18) Hz/kG2,

208Pb16O gJ= -0,16233 (39), ξT/h = 2598(18) Hz/kG2.

The molecular quadrupole moment Θ and the asymmetry of the electronic charge distribution 〈Σ(zi
2-xi
2)〉 are derived from the values of gJ, ξt , and the rotational constant B0.
gJ-Faktor der Molekeln GeO und SiS und Anisotropie ihrer Magnetisierbarkeit / Molecular gJ-Factor and Magnetic Susceptibility Anisotropy of GeO and SiS
Authors: Honerjäger R. , Tischer R.
Published: February 2015

The gJ-factor and the molecular magnetic susceptibility anisotropy ξT have been measured for 74Ge16O and 28Si32S in the vibrational states υ=0, 1, 2 and υ= 0, 1, 2, 3 respectively:

Having measured gJ and ξT as functions of υ we were able to derive the molecular and electronic quadrupole moment equally as functions of the vibrational state according to the method of Newell and Ramsey.
Drag of Bodies with Arbitrary Gas-surface Accommodation in a Free-molecule Flow
Authors: Kuščer I. , Lang H.
Published: February 2015

A body of arbitrary convex shape and uniform temperature is thought to be placed in a freemolecule gas flow. In the near-equilibrium regime the four Knudsen accommodation coefficients suffice to express the drag and absorbed heat flux. Extensions to higher speeds require more information − or assumptions − on the gas-surface interaction, as is made clear by the case with Ma ≫ 1.
ArHg+-Ions in the Mercury-Argon Low Pressure Discharge − Mass Spectrometric Analysis of the Formation Process
Authors: Franck Günter
Published: February 2015

The ion components of the mercury argon low pressure discharge are analysed with help of a quadrupole mass spectrometer. Here we have found besides the main components Hg+ and Ar+ the diatomic ion-molecules Hg2
+, Ar2
+ and ArHg+. With a discharge current of 200 mA, argon pressure 0,2 torr and mercury vapour pressure 2.8·10-3 torr, the ion components are in the ratio

[Hg+] : [Ar+] : [ArHg+] : [Hg2
+] : [Ar2
+] = 1000:134:24:10:3 .

The ratios i(ArHg+) |i (Ar2
+), i (Ar+) |i (Hg+), i (Ar2
+) |I (Ar+), i (Hg2
+) |i (Hg+) of the effusing ion currents are measured as a function of mercury vapor pressure, discharge current and argon pressure. These measurements yield the following formation processes of ArHg+ and Ar2
+:

For the products of reaction rates k and lifetimes τArm, τAr* of the metastable and highly excited Ar-atoms, we get

kArHg+
·τArm= 61·10-16 cm3,

kAr2
+·τAr*= 1.1·10-16 cm3.

So the following cross sections are found:

σArHg+ = 5.8-10-15 cm2,

σAr2
+ = 3.6-10-15 cm .
Nuclear Magnetic Resonance Studies of 43Ca
Authors: Lutz O. , Schwenk A. , Uhl A.
Published: February 2015

The ratio of the Larmor frequencies of 43Ca and 37Cl has been measured and a magnetic moment for 43Ca of μ(43Ca2+ in D2O) = -1.315645 (7) μN; has been calculated. 43Ca chemical shifts have been determined in aqueous calcium salt solutions with 43Ca in natural abundance, also at low concentrations. The latter result is interesting for 43Ca studies in biological systems.
Differential Equations and Boundary Conditions for Rarefied Polyatomic Gases
Authors: Vestner H.
Published: February 2015

Constitutive laws and differential equations for macroscopic variables in a polyatomic gas are derived from moment equations of the Waldmann-Snider equation. Constitutive laws are stated for the friction pressure tensor, the translational and rotational heat fluxes and for the tensor polarization flux. Differential equations are given for the temperature, for the difference between translational and rotational temperatures, for the flow velocity and for the tensor polarization. Boundary conditions for these four moments are obtained by Waldmanns method from the entropy production at the interface between the gas and a solid body. In particular, these are a temperature jump condition, a velocity slip condition, and equations which determine the values at the wall of the tensor polarization and of the difference between translational and rotational temperatures.
Solution of the Generalized Bethe-Goldstone Equation for 16O
Authors: Schütter J.
Published: February 2015

The generalized Bethe-Goldstone equation from the es-tlieory is used to perform a calculation in the harmonic oscillator model. It takes into account hole-hole diagrams and eliminates the model-dependent particle energies. Both effects tend to increase the binding energy and to decrease the nuclear radius.
Amplitude and Phase of Spin-Echo Signals in Bulk Metals
Authors: Kotzur D. , Mehring M. , Kanert O.
Published: February 2015

The amplitude and phase of the spin echo signal in bulk metallic material after a -β10-τ-β20 (α) pulse sequence has been calculated in the case of spin I=3/2, 5/2, 7/2, 9/2, for different ratios of the sample thickness to the skin depth. Optimal values for β10, β20 and a are obtained in the sense that the echo signal is maximized. These optimal values depend again on the spin I and the relative sample size. The theoretical results compare reasonably well with experiments, performed on 63Cu in copper foils of different size.
One Dimensional Shock Refraction at a Plasma-cold Gas Interface
Authors: Gerofi J. , Messerle H. K.
Published: February 2015

Refraction and reflection of a shockwave at a plasma/cold gas interface has been studied using an R.F. preheated section in an electrothermal shock tube. The gas used in the experiment was Argon at initial pressures from 10 to 30 Torr, with initial temperature of 9000 K.

A detailed numerical analysis of the refraction event has been undertaken using a method that does not require definition of an effective γ. Methods that do use such a γ are not accurate, except for very weak shocks. Because of short ionization times it has been possible to assume equilibrium behind the various shock waves. Calculations suggest that in the region of interest, reflected and refracted shock velocities depend primarily on initial shock velocity, slightly on initial plasma temperature and very weakly on initial pressure. The analysis covers initial temperatures of 6000 to 12 000 K and initial pressures of 10 to 50 Torr.

Calculations and experimental results are presented. These show that a step function discontinuity is a good approximation to the nature of the plasma cold gas interface in this situation.
Thermodynamische Zustandsgrößen von Alkalimetallplasmen und von deren Komponenten / Thermodynamic Properties of Alkali Metal Plasmas and of their Components
Authors: Reiter F. W.
Published: February 2015

Thermodynamic functions of plasmas of alkali metals and of their components - diatomic molecules, atoms, simply charged ions and electrons - are calculated in the temperature range 298.15 °K -10000 °K. At this it is supposed, that the plasma is in thermodynamic and chemical equilibrium and in an ideal gas state.

The internal partition functions of the components of the plasmas are calculated by summation term by term up to characteristic quantum numbers. These characteristic quantum numbers are determined by graphic and calculating methods.

The thermodynamic functions of alkali metal plasmas and their components are discussed and compared with results calculated by approximative methods.
Reflexion von Clusterstrahlen an einem Echelettegitter / Reflection of Cluster Beams on an Echelette Grating
Authors: Mayer H.
Published: February 2015

Nitrogen cluster beams are reflected from an Echelette grating to investigate the influence of the surface structure on the reflection characteristics. If the mean cluster diameter is greater than the effective grating constant the same flux distribution is found as for a polished reflector. However, the flux distribution clearly spreads out in the plane of incidence if the cluster diameter becomes almost equal to the effective grating constant.
Elektronenmikroskopische Überprüfung der röntgenographischen Linienbreitenanalyse nach Hall
Authors: Tschegg E. , Wagendristel A. , Skalicky P.
Published: February 2015

In the submicroscopic range crystallite sizes which are determined by means of various X-Ray methods show often considerable discrepancies .The reason for this are different analytical approximations made in the underlying theories of these methods. The results of the analysis of the X-Ray line width of wet-milled alluminium powder are compared with crystallite sizes which were obtained by dark-field electron mircoscopy. The basic method was Hall's analysis using different elimination procedures for apparative parameters and grain-size and internal strain contributions. The best agreement with the electron microscopic data was obtained by the Wagner-Aqua method combined with an approximation of the strain- and particle size profiles by Gaussian functions.
Zusammenhang zwischen Schweratominduzierter Fluoreszenzlöschung und Termschema von mehrkernigen aromatischen Kohlenwasserstoffen / Correlation between Heavy-atom induced Fluorescence Quenching and Energy Levels of Polynuclear Aromatic Hydrocarbons
Authors: Dreeskamp H. , Zander M.
Published: February 2015

The observation that the fluorescence of certain polynuclear aromatic hydrocarbons (perylene, 1.2 ;5.6-dibenzoperylene, 9.10-diphenylanthracene and rubrene) is quenched by alkyl iodides only slightly is explained on the basis of the energy levels of these hydrocarbons. In these systems an effective radiationless desactivation of the fluorescing state S1 by intersystem crossing into the triplet manifold is prevented by a wide energy gap between S1 and the lowest triplet state, and the absence of excited triplet states below s,.
Bestimmung von Komplexen in Alkalichloroaluminat-Schmelzen aus Aktivitätsmessungen / Determination of Complexes in Alkalichloroaluminate-Melts from Activity Measurements
Authors: Schulze K. , Steinle D. , Hoff H.
Published: February 2015

The activity of aluminiumchloride in NaCl-, RbCl-, CsCl-containing electrolytes has been measured by the formation cell Al(s)/AlCl3-MeCl(1)/Cl2(g)/C. The EMF depends strongly on the ratio of AlCl3: MeCl and is characterized by a steep decrease of the equimolar composition. Accounting for three coupled equilibria between the 5 species Al2Cl7
−, Al2Cl6, AlCl4
−, Al3+, Cl− the activity as a function of concentration can be calculated very precisely. The distribution of the aluminiumchlorocomplexes is discussed for varying melt compositions.
A Perturbation Molecular Orbital Study of the Recombination Reactions of Diarylaminyl Radicals
Authors: Shanshal Muthana
Published: February 2015

The recombination reactions of arylaminyl radicals are studied on the basis of its order P\10 treatment, assuming dimeric intermediates with C-N or C-C bonding modes. In the case of diphenyl aminyl radical the N -N recombination causes an increase in the T-bonding energy and should be most favourable for the low temperature reactions. Due to the low dissociation energy of the N-N bond, the C-N bonding is preferred in the high temperature reactions. It is found that the ortho- and para-additions are energetically more favourable than the meta addition, in agreement with π-SCF MO calculations and experimental results. The recombination of 2,2′-dinaphthyl aminyl radicals proceeds through C-C and C -N bonding, the 1,1′-bonding is most favourable. The PMO-results are parallel to those of the π-SCF MO calculations, providing another demonstration for the utility of this method.
Experimentelle Bestimmung der öffnungsfehlerkonstante von Elektronenkanonen / Experimental Determination of the Spherical Aberration Constant of Electron Guns
Authors: Lauer Rolf
Published: February 2015

Due to the spherical aberration of electron guns, rays with large inclinations will not pass through the cross-over (the image of the entrance pupil). In order to calculate the constant of spherical aberration, it is necessary to know the transverse aberration as a function of the ray inclination at the cathode. Because measurements near the cathode are not possible, the size of the entrance pupil has been determined by theoretical considerations. The additional knowledge of cross-over size and inclinations of the emerging rays is then sufficient for obtaining the ray data at the cathode. The cross-over has been determined indirectly, ray inclination and transverse aberration in the cross-over plane have been measured by means of a shadow method.
Berichte: Mach's Principle - A Critical Review
Authors: Reinhardt Michael
Published: February 2015

After a short historical introduction it is discussed how far Mach's principle is incorporated into general relativity. The possible role of Mach's principle as a selection rule for the solutions of Einstein's field equations is summarized. Then follows a discussion of Math's principle in theories of gravitation other than Einstein's, mainly the Brans-Dicke theory. Finally the experiments on the isotropy of inertial mass and their consequence for Mach's principle are described. The conclusion is that Mach's principle, though an extremely stimulating thought, has at present little claim to be a basic physical principle.
The Dynamic Stark-Effect in a Turbulent Hydrogen Plasma
Authors: Rutgers W. R. , Kluiver H. de
Published: February 2015

The profiles of the first three Balmer lines of hydrogen are measured in a turbulent heating experiment. From the position of Stark satellites the field strength of low frequency oscillations (ω ~ ωpi) is calculated. The energy density in these electrostatic oscillations can amount to 1% of the therm al energy. The presence of high frequency oscillations (ω ~ ωpe) is concluded from satellites near ± ωpe from the unperturbed line position.
Induktive Plasmabeschleunigung mit nicht-sinusförmigen stehenden elektromagnetischen Wellen / Inductive Plasma Acceleration with Non-Sinusoidal Elektromagnetic Standing Waves
Authors: Köhne R. , Meert A.
Published: February 2015

Some types of standing r. f. waves are compared and discussed. As a result a new type of a non-sinusoidal standing wave is proposed which leads to an improved inductive acceleration system. Plasma velocity measurements have been carried out on this system. Numerical calculations are made for the plasma acceleration process and compared with the experimental values of the velocity. The theory as well as the advantage of the proposed system is verified by the results.
Berechnung der Bandstrukturen nichtstöchiometrischer Vanadiumcarbide VCx / Band Structure Calculations on Nonstoichiometric Vanadium Carbides VCx
Authors: Neckel A. , Rastl P. , Schwarz K. , Eibler-Mechtler Renate
Published: February 2015

Using the augmented-plane-wave (APW) method the electronic structure of stoichiometric vanadium carbide has been computed previously 1. Since only nonstoichiometric cubic phases of vanadium carbide are stable and all experiments are made with such samples, the energy bands have been determined for some nonstoichiometric VCx; phases (x = 0.87; 0.833; 0.79; 0.75) using the APW virtual crystal (VCA) approximation similar to Schoen’s work on TiO 7, 10. Our approach differs from his in two aspects: First, the potential is constructed from the self consistent potential of Ref. 1 instead of using atomic data. Thus, the important self consistent procedure is taken into account at least in an approximated form. Second, a more realistic scheme for occupying the states is suggested. Furthermore, an attempt is made to normalize the wave functions in order to obtain the charge distribution in the crystal.

The density of states and the partial densities of states corresponding to the quantum numbers n and l have been computed using an LCAO interpolation scheme. The different VCx phases show a fairly “rigid band structure” . The Fermi energy and the density of states at the Fermi level increase with decreasing carbon content. The calculated APW- as well as the LCAO-charge distribution indicate -in accordance with ESCA measurements 32 -that the charge-transfer from vanadium to carbon and the ionicity of VCx decrease with increasing vacancy concentration. The results of X-ray-emission and heat capacity measurements are discussed in terms of the APW-VCA results. Especially for the X-ray-emission data the agreement between theory and experiment is fair.
The Urbach Rule for the Sodium- and Potassium-Halides
Authors: Tomiki Tetsuhiko , Miyata Takeo , Tsukamoto Hirokazu
Published: February 2015

Phenomenological and physical aspects of the intrinsic tail spectra of the alkalihalides are studied referring to the new results on the intrinsic tail spectra of KBr and KI and to the temperature dependences of the lowest-energy Γ-exciton peak of the sodium- and potassium-halides. Systematically analysing the temperature dependence of the steepness parameter σs (T) of the Urbach rule for these halides, it is found that the frequency factor has the value nearly equal to the acoustic phonon energy at X or L of each host lattice and the steepness constant σs0 becomes larger in passing from fluoride to iodide. This halogen dependence of σs0 is discussed in terms of the hole band-mass of the Γ8-level.
Photodissociation of Carbon Dioxide in the Mars Upper Atmosphere
Authors: Barth Charles A.
Published: February 2015

Photodissociation of carbon dioxide produces O (1S) atoms and CO (a3Π) molecules in the Mars upper atmosphere. Calculations of the emission rate of the atomic oxygen 2972 Å line and the carbon monoxide Cameron bands produced by the photodissociation mechanism are factors of 3 and 10, respectively, smaller than the emission rates observed by Mariner ultraviolet spectrometers. Laboratory measurements are needed to understand the discrepancies.
Begleitbanden der Null-Phononenlinien des Phosphoreszenzüberganges dotierter Cr3+: Alha6J3-Einkristalle. Teil II. Gitterschwingungen in Alha6J3 / The Sidebands of the zero Phenon band of the Phosphorescence Transition in Cr3+ : Alha6J3 Single Crystals. 11. Vibrational Lattices in Alha6J3
Authors: Krasser W. , Koglin E. , Wolff G. , Nürnberg H. W.
Published: February 2015

The optical phonons of an Al(ha)6J3 single crystal are measured in dependence of the polarisation of the incident and scattered light waves at K ≈ 0. The phonons are assigned to the irreducible representations according to the correlation method. At low wavenumbers, two intensive bands are found, which are assigned to vibrational modes of the aluminium and iodine atoms. The iodine atoms are classified according to irreducible representations of the site symmetries Ci and C2. The Raman spectrum suggests definitely the site symmetry C2. The phonons of the urea molecules agree with the phonons of a pure urea crystal except for small frequency shifts. Besides there are measured some vibrational bands in the range of 200 -450 cm-1, which result from vibrational modes caused by the coordinative bonding of the urea molecules via their oxygen atoms to the aluminium ions.
Isotopenfraktionierung im Sauerstoffzyklus der Erde / Isotope Fractionation occuring in the Oxygen Cycle
Authors: Wagener K.
Published: February 2015

The present data on isotope fractionation factors involved in the oxygen cycle are reviewed. Physical models for the isotope fractionation of respiratory processes and photosynthesis on land as well are discussed. The consistency of all data is examined on the basis of a 2 box model (atmosphere and an ocean surface layer containing 90% of marine biomass). From this balance, the O2 exchange rate between the two reservoirs results as 1/3 of the marine production. This seems to be too low and therefore indicate that either one figure is bad or the isotope exchange between CO2 and O2 is more important than expected.
The Oxidation of Formyl Radicals
Authors: Washida N. , Martinez Richard I. , Bayes Kyle D.
Published: February 2015

Steady state concentrations of formyl radicals were measured with a photoionization mass spectrometer. The reaction of ethylene with oxygen atoms in a system free of O2 was used to form CHO and CH3. Preliminary experiments showed that the reaction of methyl radicals did not interfere with the CHO measurements. By using low concentrations of O and short reaction times, it was possible to observe the initial growth of the CHO concentration. From the rate of approach of CHO to its steady state concentration, the absolute rate constant for the reaction O + CHO was determined to be (2.1+0.4)×10-10 cm3 molecule-1 sec-1. Addition of molecular oxygen to this system caused a decrease in the steady state CHO concentration, due to the reaction,

CHO+O2→HO2+C0

as was suggested by Groth and coworkers in 1938. The rate constant for this reaction was calculated to be (5.7±1.2)×10-12 cm3 molecule-1 sec-1. The importance of these rate constants for combustion and atmospheric reactions are discussed briefly.
Nuclear Relaxation and Slow Diffusive Motions in CaF2 and NaF
Authors: Steenwinkel R. Van
Published: February 2015

Fluorine relaxation times T1Z , T1D and T2 are measured as functions of temperature in single crystals of CaF2 and NaF. Typical quantities like the activation energy for vacancy diffusion and the formation energy of defect pairs are deduced and reported.
The Line Shape of Optical and Electron Spin Resonance Absorption under the Influence of Exciton Motion
Authors: Reineker P.
Published: February 2015

The line shape of optical and electron spin resonance absorption under the influence of the coupled coherent and incoherent exciton motion is calculated analytically. The exciton motion is described by a stochastic Hamiltonian comprising both its coherent and its incoherent part. The coherent motion is represented by the transition matrix element and the incoherent one by the strengths of local and non-local fluctuations. Starting from this Hamiltonian, equations of motion of two-time correlation functions for two arbitrary operators are derived. Using these equations, the line shape of optical absorption of crystals containing two inequivalent molecules per unit cell is calculated. Furtheron an exact analytical expression for the ESR line shape of two differently oriented molecules is derived and discussed in detail as a function of the parameters of the model. From this exact expression for the line shape approximations for several limiting cases are obtained. A comparison between the exact and the approximate expressions is given.
Investigations on the Rupture of the N-N-Bond within the Anodic Oxidation and Catalytic Decomposition of Hydrazine
Authors: Arnolds K. , Heitbaum J. , Vielstich W.
Published: February 2015

Mass spectrometrical measurements of the off gas composition formed in the anodic oxidation or catalytic decomposition of hydrazine at platinized platinum, Raneynickel and amalgamated sintered nickel as electrocatalysts show that only up to 4% of the oxidation of hydrazine occurs via N -N-bond splitting.
Observation of a 2 s Activity from Irradiation of Rhenium with Higher-Energy Deuterons
Authors: Jahn P. , Mayer-Böricke C.
Published: February 2015

Following the irradiation of rhenium with deuterons of 45 to 80MeV a 184 keV γ-line was observed which decayed with a half-life of 2.0 ±0.2 s. A tentative assignment of this activity to 183Os is derived on the basis of yield ratios.
Electric Polarization Caused by a Diffusion Flow in a Polar Gas Mixture
Authors: Hess S.
Published: February 2015

The kinetic theory of the diffusio-electric polarization is developed analogous to the previously treated thermo-electric polarization (Waldmann, Hess 1969). The relevant constitutive law is derived. The characteristic coefficient determining the magnitude of this effect is related to collision integrals obtained from the Waldmann-Snider equation. A simple model calculation shows that this coefficient will be nonzero, in general, and of measurable size, for polar symmetric top molecules
Scattering of Ions V. Elastic Scattering of the Symmetric Rare Gas Ion — Rare Gas Atom Systems
Authors: Mittmann H.-U. , Weise H.-P.
Published: February 2015

Differential cross-sections for the elastic scattering of Ne+ on Ne, Ar+ on Ar, Kr+ on Kr, and Xe+ on Xe have been measured. In the lab.-energy range from 3 eV up to 30 eV a rainbow maximum was observed and attributed to the attractive ground state potentials of these systems. From the angular positions of the primary rainbows the potential depths were derived. In the case of Ne2
+ and Ar2
+ these values are compared with the results of quantum chemical calculations and of semiempirical estimates. From lowest energies up to Eʟ = 200 eV g-u-interference oscillations were observed for all systems. In the case of Ne+ -Ne two oscillatory structures with different frequencies were detected and attributed to interference between Π-states and Σ-states, respectively. With increasing atomic number of the rare gas atoms the g-u-structure becomes increasingly irregular. The measured angular distances were used to derive the potential energy difference between the interfering molecular states. The evaluation was carried out by varying parameters of analytical model potentials for the lower lying state and the difference potential until the quantum mechanically calculated differential cross-section agreed with the experimental one within the experimental error. In the case of Ne2
+ and Ar2
+ the results are compared with ab initio calculations and experimental results of other authors. For Kr+ -Kr and Xe+ -Xe a fit at all energies could not be obtained with a single set of parameters. This effect and the high irregularity of the experimental curves are attributed to fine structure splitting of the molecular states via the strong spin-orbit coupling in Kr and Xe
Barkhausen-Spektren von Eisen bei 300 K und 77 K / Barkhausen Spectra of Iron at 300 K and 77 K
Authors: Deimel P. , Waas A. , Daniel H.
Published: February 2015

Barkhausen spectra of iron have been measured at 300 K and 77 K. At the lower temperature less Barkhausen jumps were registrated. The large jumps disappeared almost completely. The dependence of the Barkhausen spectra on the slope of the hysteresis curve was also measured
A Single-mode Dye Ring; Laser with Output Coupler Using Frustrated Total Internal Reflection
Authors: Marowsky Gerd
Published: February 2015

Details of a dye ring laser with an output coupler of adjustable transmission based on frustrated total internal reflection are reported. The construction allows optimization of tuning range or output power. Using appropriate intracavity etalons and a Fox-Smith reflector as mode selector reliable single-mode operation was observed with peak powers of 1 kW and bandwidths of 0.03 pm
Investigations on Instabilities of Electric Arcs
Authors: Ragaller K.
Published: February 2015

A general formalism is derived, that allows the evaluation of magnetic instabilities of all types of electric arc.

It is shown that a stability criterion exists which is determined by the interaction between the magnetic forces, the frictional force and the so-called isotherm movement. This criterion can be expressed in terms of a dimensionless parameter Mk: when Mk is smaller than a critical value Mkcr, then the arc is absolutely stable, when Mk = Mkcr a stationary, deflected condition arises, and when Mk>Mkcr the arc is unstable. Depending on the magnitude of the growth rate however, a convective stabilisation, caused by an axial flow component, can result.

The results of the theory are applied to a variety of technically interesting arcs, such as axially blown arcs, arcs in gaps and transversely blown arcs.
The Millimeter Wave Spectrum of DCNO: An Example of Current Measurements in the Frequency Range from 60 to 350 GHz
Authors: Winnewisser Manfred , Winnewisser Brenda P.
Published: February 2015

An efficient system for preliminary data reduction is described which completes a recently developed data acquisition and reduction system for the measurement of millimeter wave absorption lines with the help of a dedicated computer. A simple method of automatically determining the absorption line centers is given.

Rotational transitions of DCNO, measured with the above system, are reported for the ground state and the first excited state of each of the two bending modes ν4 and ν5. The rotational and rotation-vibration constants obtained for these states are

B0 = 10,292.48340 (31) MHz, D0 = 3.5418 (10) kHz,

Bν4 = 10,306.00780 (45) MHz, Dν4 = 3.6409 (22) kHz,

Bν5 = 10,338.65942 (32) MHz, Dν5 = 3.6208 (16) kHz.

The l-type doubling constants q.t
0) and qt
(1) agree with the values obtained previously from direct l-type doubling transitions.
Conformation and Mobility of Radicals in Heterogeneous Systems ESR Spectra at 4K of Methyl, Ethyl, n-Propyl and Allyl Radicals Adsorbed on Silica Gel
Authors: Shiga Tetsuo , Yamaoka Hitoshi , Lund Anders
Published: February 2015

ESR spectra of the methyl, ethyl, n-propyl and allyl radicals adsorbed on silica gel were analysed in terms of g-factor and hyperfine coupling anisotropies. The magnitudes of the anisotropies demonstrate that at 4 K the methyl radical reorients about its threefold axis, and the ethyl radical reorients about the C -C-bond axis. The experimental data for the methyl and ethyl radicals have been combined to yield the dipolar hyperfine coupling for an α-proton. The constants thus derived are Bx=12.5G , By= -13.0 G and B2= 0.5 G. The n-propyl radical has a rigid conformation at 4 K with a spectrum which arises by the hyperfine interactions of two α protons and two β protons. The β protons have aβ1 = 40 G and aβ2 = 22 G, which is indicative of an asymmetric conformation. The allyl radical at 4 K also gives the rigid limit spectrum. The temperature dependence of the spectra was studied in the range 4K - 183K.
Knudsen Corrections for the Senftleben-Beenakker Effect of Viscosity
Authors: Vestner H.
Published: February 2015

A rarefied polyatomic gas between infinite parallel plates which is subject to a pressure gradient and to a magnetic field is considered. The tensor polarization and the Kagan polarization account for the influence of the field on the gas flow. In the slip flow regime differential equations and boundary conditions for the velocity and the tensor polarization are solved. The dependence of the solution on the mean pressure and on the magnetic field is discussed. Knudsen corrections for the Senftleben-Beenakker effect of viscosity are derived. By comparison with experimental data of Hulsman et al. a set of surface parameters is obtained. They characterize mechanical slip, thermomagnetic slip, and the influence of gas-wall collisions on the tensor polarization.
Radiation Field of a Uniformly Moving Charge in an Anisotropic Medium
Authors: Sastry G. P. , Majumdar S. Datta
Published: February 2015

Fourier integrals are set up for the field of a point charge moving uniformly in an arbitrary direction in a uniaxial medium anisotropic in ε only. The integrals break up into several parts two of which yield the ordinary and extraordinary cones with uniform azimuthal potential distribution. The remaining integrals neither contribute to the energy radiated nor affect the size and the shape of the cones, but merely distort the field within the cones. The integrals are evaluated exactly in the non-dispersive case and closed expressions for the potential are obtained. In the dispersive case, the radiation field is determined by using the asymptotic form of the Hankel functions occurring in the integrand. The resulting expressions exhibit the high azimuthal asymmetry characteristic of anisotropic fields. From the expressions derived for a pure dielectric the potential in a doubly anisotropic medium is obtained, without a fresh calculation, by making appropriate substitutions for the coordinates of the field point and the components of the dielectric tensor.
Normal Coordinate Analysis and Mean Amplitudes of Vibration of Halate Ions
Authors: Sanyal Nitish K. , Dixit L.
Published: February 2015

A normal coordinate analysis of halate ions, viz. 35ClO3
-, 37ClO3
-, Br16O3
-, Br18O3
- and IO3
- has been carried out using a general valence force field and Wilson’s F -G matrix approach. Mean amplitudes of vibration for bonded halogen-oxygen and non-bonded oxygen-oxygen distances have been reported using Cyvin’s method and Müller’s L-matrix formalism. Effects of isotopic substitution and isotope frequency shifts are also examined.
Study of the C-D Stretching Vibration Bands v1 of DCCF and DCCBr
Authors: Huhanantti Mikko
Published: February 2015

The rotational structures of the ν1 bands of the deuterated monohaloacetylenes DCCF and DCCBr were investigated. The rotational constants B in the ground state and in the vibrational states involved were obtained. The centrifugal distortion constants D were calculated from the force constants and the geometrical data, too. The results D = 8.7 x 10-8 cm-1 for DCCF and D = 1.9 x 10-8 cm-1 for DCCBr are compatible with the experimental values (12 ± 4) x 10-8 cm-1 and

(2±2) x 10-8 cm-1, respectively.
Schwingungsberechnungen der isotopen VOCl3-Moleküle, des VOBr3 und der Verbindungen VOCln Br3-n , sowie einige Molekularkonstanten der Titelverbindungen
Authors: Hovdan H. , Cyvin S. J. , Brockner W.
Published: February 2015

In order to determine the isotopic splittings of the vibrational frequencies of isotopieally substituted vanadium oxytrichloride and to present the correlation between VOCl3 and VOBr3 a set of force fields was constructed for the isotopic species of VOCl3 , VOCl2Br, VOCIBr2, and VOBr3 . The conventional descriptions of the fundamentals are supported by the calculated potential energy distribution in all cases. Furthermore the calculations of certain molecular constants such as the mean amplitudes, their corresponding K-values, the Coriolis coupling constants of the

-type and some thermodynamic quantities have been performed.
Transport Processes in TlI and in the AgI-TlI-System
Authors: Sdiiraldi A. , Magistris A. , Pezzati E.
Published: February 2015

The transport properties of TlI and of the system AgI -TlI were investigated by measuring the electrical conductivity, σ , and the electronic and ionic transport numbers. A particularly high electronic conductivity was detected in β-TlI, while the a phase showed a predominant anionic contribution, as in TlCl and TlBr. The intermediate compounds, AgTl2I3 and AgTlI2, are silver ion conductors, but they exhibit low σ values. A comparison with other poliiodides, with a high silver ion conductivity, is suggested on the basis of the crystal bond ionicity.
Mikrowellenrotationsspektren der Molekeln CsF, CsCl, CsBr und CsI
Authors: Honerjäger R. , Tischer R.
Published: February 2015

Microwave rotational spectra of the cesium-halides have been measured in the 1 cm-wavelength region and could be extended to relatively high vibrational states. The results were combined with Gordy’s mm-mavelengths and yield the 8 Dunham energy coefficients Y01, Y11 , Y21 , Y31 , Y02, Y12,Y03 and Y04.
Experimental Study of Stark Broadening of the Allowed and Forbidden Transitions 23P-43D, 4 3F (λ=4471.5 Å, λ=4470 Å) in Neutral Helium
Authors: Drawin H. W. , Ramette J.
Published: February 2015

Measurements were made of the profile of the Hel 4471.5 Å line and its forbidden component at λ = 4469.9 Å, emitted from an afterglow plasma of electron densities in the range 2.2 × 1014 to 1.5 × 1015 cm-3. The various quantities which define position and form of the profile have been compared with the theoretical calculations of Griem and of Barnard et al. It has been found that the wavelength shifts of the individual components and, thus, the peak separation are slightly smaller than predicted by theory, whereas the intensity in the valley between the two components is found to be slightly larger than the theoretical values. The peak intensity of the forbidden component is smaller than given by theory but not as small as found by D. D. Burgess and C. J. Cairns. At low electron densities the intensity of the forbidden component is proportional to the square of the normal field strength F0 of the electric microfield. At higher electron densities the intensity increases proportionally to F0 in agreement with the transition from quadratic to linear Stark effect at higher electric field strengths. The measurements show that the influence of the ion dynamics on the line profile is probably not as large as assumed by D. D. Burgess. The measurements show that the position of the intensity minimum between allowed and forbidden component is shifted towards the allowed component when the temperature decreases.
Plasma Capacitor with Ion Acoustic Waves
Authors: Leuterer F.
Published: February 2015

We examine experimentally and theoretically the r. f. potential within a capacitor, filled with a homogeneous plasma in a magnetic field and driven at frequencies ωci <ω<4ωci . We assume the ions to be cold, and the electrons to have a Maxwellian velocity distribution along the magnetic field, but zero radius of gyration. Thus ion acoustic waves are included. The whole kz-spectrum of the exciter is needed to explain the experimental results.
Theory of Shock-Wave Ionization upon High-Velocity Impact of Micrometeorites
Authors: Drapatz S. , Michel K. W.
Published: February 2015

The relevant processes in shock wave ionization of a solid Fe micrometeorite impinging on a W target are analyzed. The internal energy behind the shock wave in shown to depend on impact velocity w, target and meteorite density in a simple analytical form. For low impact velocities (w<7 km sec-1) the ions generated by the shock are mostly due to surface ionization. For high impact velocities [w>20 km sec-1) the number of ions can satisfactorily be explained by isentropic expansion of the shocked material to a particle density of n ≈ 1020 cm-3 whereupon the rate processes in the expanding ion cloudlet govern the residual ionization. In velocity regions where laboratory measurements can be carried out, the agreement between theory and experiment confirms the assumptions made.
Zur Theorie der Elektronenübergangsreaktionen in molekularen Komplexen / Theory of Electron Transfer Reactions in Molecular Complexes
Authors: Schmidt P. P.
Published: February 2015

This paper reports a theory of the inner sphere-type electron transfer reaction. Inner sphere reactions, as opposed to the outer sphere variety, require that the solvate or ligand shells surrounding the electron donor and acceptor species undergo considerable change in the course of the electron transfer. In this paper we assume that the electron transfer step takes place in a molecular complex which exists in equilibrium with the reactants. The electron transfer step occurs as a non-radiative charge transfer-type transition. In this manner we treat the charge transfer kinetics, in particular, the evaluation of the reaction rate constant, in the same manner as is usual for non-radiative problems. The analysis leading to the rate constant expression is based on Yamamoto’s general chemical reaction rate theory. The rate constant expressions obtained are quite general, they hold for any degree of strength of coupling between subsystems comprising the entire system. The activation energy, in the Arrhenius form for the rate constant, shows a dependence on the energy (work) of formation of the intermediate charge transfer complex, on vibrational shift energies associated with the molecular motions of the ligands, and on solvent repolarization energies. The activation energy also shows an important dependence on coupling terms which link the vibrations of the molecular inner shell with the polarization states of the (assumed) dielectric continuum which surrounds the charge transfer participants. The approach we take in developing this theory we believe points the way towards the development of a more complete theory capable of accounting for the dynamics of the molecular reorganization leading to the intermediate charge transfer complex as well as accounting for the electron transfer step itself.
Tracer Impurity Diffusion in Liquid Metals: In in Gallium and Ga in Indium
Authors: Eriksson P. E. , Larsson S. J. , Lodding A.
Published: February 2015

Diffusion measurements have been made for 114In in Ga between 20° and 455 °C, and for 72Ga in In between the m.p. and 380 °C. Linear plots of D vs T describe the results about equally well as Arrhenius representations. The Arrhenius parameters are D0 = 2.1 · 10-4 cm2/S, Q = 1.64 kcal/mol for In in Ga, D0 = 2.4 · 10-4 cm2/S, Q = 1.93 kcal/mol for Ga in In. Ga diffuses faster than In in both matrices. The effective activation energy of Ga is much higher than that of In in the lighter solvent, but the opposite is the case in In. Simple electrostatic screening arguments cannot be applied to the latter results. A recent model, predicting a nearly linear temperature dependence of D, appears somewhat better applicable.
Fredholm Approximations in the Scalar Bethe-Salpeter Equation
Authors: Bauhoff W.
Published: February 2015

The Fredholm approximation is discussed in the framework of the scalar Bethe-Salpeter equation. The trace of the angular momentum decomposed kernel is expressed in terms of Feynman parameter integrals which shows the relation to the vertex function. A new derivation for this representation is given which is far more direct than the previous one. Using this representation, several general features of the eigenvalues are discussed. For special cases, the trace is computed explicitly, and the numerical values are compared with the exact ones, obtained by variational methods.
Neutron Star Matter and Neutron Star Models
Authors: Heintzmann H. , Hillebrandt W. , El Eid M. F. , Hilf E. R.
Published: February 2015

Various methods to study the ground state of neutron star matter are compared and the corresponding neutron star models are contrasted with each other. In the low density region ρ < 1014gr cm-3 the nuclear gas is treated here by means of a Thomas Fermi method and the nuclei are described by the droplet model of Myers and Swiatecki. For ρ > 1014 gr cm-3 both standard Brueckner theory with more realistic interaction (one-boson-exchange) potentials and the semiphenomenological theory of Fermi liquids (together with the standard Reid softcore potential) are applied to neutron star matter. It is shown that while the high mass limit of neutron stars is hardly affected, some properties of lowmass neutron stars such as their binding depend sensitively on these refinements. Various tentative (but unreliable) extensions of the equation of state into high density regime ρ > 1015 gr cm-3 are investigated and it is shown that the mass limit for heavy neutron stars lies around 2.5 solar masses. It is further shown that a third family of stable (hyperon) stars is not forbidden by general relativistic arguments if there is a phase transition at high densities.
The Influence o f Excited States on the Reactive Thermal Conductivity of an L.T.E.Hydrogen Plasma
Authors: Capitelli M.
Published: February 2015

The influence of excited states on the reactive thermal conductivity of an L.T.E. hydrogen plasma has been studied by making realistic assumptions on the cross sections of these species.
Tracer Impurity Diffusion in Liquid Metals: Au in Ga
Authors: Eriksson P.-E. , Larsson S. J.
Published: February 2015

The diffusion coefficient of 198Au in liquid Ga has been measured between 35 and 460 °C. The results can be represented by a linear plot of D vs T or by an Arrhenius plot. The latter yields the parameters D0 = 4.9·10-4 cm2/s and Q = 2.65 kcal/mol. However, some distinct departures from the straight line characteristics, showing a considerably higher “activation energy” at the low temperatures, suggest the possibility that clusters composed of two or several atoms may partake in diffusion.
Beziehungen zwischen chemischer Verschiebung und Ladungsdichte. II / Relations between chemical shift and charge density. II
Authors: Sterk H. , Holzer H.
Published: February 2015

It has been shown that the chemical shift of protons in aryl-ortho-diketo compounds is not better represented by adding the electric fieldeffect, proposed by Buckingham, to the charge density calculated by CNDO II.
On the Assignment and Directional Dispersion of Polar Phonon Modes in K3Cu(CN)4 and K3Ag(CN)4
Authors: Nitsch W. , Falge H. J. , Claus R.
Published: February 2015

Polar phonon modes in single crystalline K3Cu(CN)4 and K3Ag(CN)4 have been experimentally studied by light scattering. Measurements at 293, 82 and 6 K made possible assignments in the low frequency region from 0 to about 700 cm-1 and the high frequency region from 2030 to about 2100 cm-1 originating from the C≡N stretching vibrations. Directional dispersion due to the anisotropy of K3Cu(CN)4 has been studied and allowed the identification of the transversal and longitudinal vibrations in the high frequency region. IR-reflectivity measurements, partly on the basis of the ATR-method, have been used in order to support the assignments in this region.