bluuebunny/crossref_metadata_2025_split huggingface dataset:
Der Gültigkeitsbereich der Molièreschen Näherung/ The Range of Validity of the Molière Approximation
Authors: Lehmann H. , Schoenebeck H. 
Published: February 2015

Abstract
The Moliere approximation of the scattering amplitude is, following earlier statements, a high-energy and small-angle approximation. Recent investigations show that there is no intrinsic small-angle restriction, the restriction being due to special derivations. A method is given, to obtain the scattering amplitude in the Moliere approximation without small-angle assumption. This enables to evaluate electron backscattering rates with the aid of the Moliere scattering amplitude.
Spektrum explodierender Drähte in verschiedenen Atmosphären. Messung des Dissoziationsgrades des umgebenden Gases und des Drucks im Plasma/Spectrum of Exploding Wires within Different Atmospheres. Measure of Dissociation Rate of Surrounding Gas and of Plasma Pressure
Authors: Triché C. , Perarnau G. 
Published: February 2015

Abstract
The explosion of a copper wire is caused by means of a discharge from a pulsed source. We observe a continuous spectrum with characteristic emission and absorption lines. The degree of dissociation of the surrounding gas and the pressure of the plasma can be determined from the width of an absorption line.
Thermodynamic and Structural Properties of Molten CsCl as Obtained by Computer Simulation
Authors: Margheritis Chiara , Sinistri Cesare , Flor Giorgio 
Published: February 2015

CsCl was computer simulated using the Monte Carlo (MC) method on the basis of interionic pair potentials. Calculations were carried out at constant pressure (1 atm) and at different temperatures covering the liquid phase. The thermodynamic and structural properties thus obtained were in good agreement with the corresponding experimental values when available.
A discussion of these properties in relation to those of CsBr and Csl was also carried out. Finally the polarization energy of CsCl along with those of CsBr and Csl, was compared with the results that can be obtained using simpler models recently proposed
Consequences of Restricted Defect Diffusion on NMR and Dielectric Relaxation
Authors: Kimmich R. 
Published: February 2015

Abstract
Nuclear magnetic and dielectric relaxation formulas are given for a model of limited diffusion of defects. The limitation is introduced by the assumption of fixed reflecting barriers on both sides of the defect. The diffusion process is assumed to be one-dimensional and continuous. The effect of the finite length of the defects is included in the presented treatment.
Mass Spectrometric Determination of Activities and their Dependence on Temperature in Liquid Bismuth-Tin Alloys
Authors: Riekert G. 
Published: February 2015

Abstract
Liquid alloys of the Bi-Sn system have been studied to determine thermodynamic properties. Ion currents have been measured by a double-focusing mass spectrometer. The thermodynamic values were calculated by application of the monomer-dimer ratio technique and the integration technique. Special attention was paid to the correction of fragmentation effects.
Activities of both components versus composition in the temperature range from 1023K to 1323K and values of Gibbs energies and heats of mixing are reported as results. At 1200K the species Bi2 , Bi3, Bi4 , BiSn, and Bi2Sn were observed in the gaseous phase above the Bi50Sn50 alloy. The discussion shows a tendency to segregation of the liquid Bi-Sn alloys.
Note on Population Densities in an Expanding Helium-Neon Plasma Flow
Authors: Nishida Michio 
Published: February 2015

Abstract
The axial population distributions in an expanding helium-neon mixture plasma flow have been calculated for three cases of the concentration of neon ions. The results show that the electron temperature distributions are strongly dependent on the concentration of the neon ions and that the populations of the upper levels of the helium atom depend on the electron temperature near downstream and on the flow expansion far downstream.
Untersuchung zur externen Spin-Bahn-Kopplung bei aromatischen Molekülen / External Spin-Orbit-Coupling in Aromatic Molecules
Authors: Friedrich J. , Weinzierl G. , Dörr F. 
Published: February 2015

Abstract
The influence of ethylhalogenes on the polarization of the phosphorescence of naphthalene was studied by means of the photoselection technique. It is shown that with increasing concentration and with increasing nuclear charge of the heavy atom the phosphorescence of naphthalene becomes increasingly depolarized. The influence of the external heavy atom on the Tx- and Tz- substate is stronger than on the Ty-substate. From the concentration dependence of the depolarizatign conclusions concerning the mechanism of the external spin-orbit-coupling are drawn. The dirept spin-orbit-coupling mechanism is ruled out. In the model discussed the variation of the external heavy atom effect with the intermolecular distance is related to overlap integrals.
Liquid Crystalline Phases in N-(4-n-alkylbenzylidene)-4′-n-alkylanilines
Authors: Nehring Jürgen , Osman Maged A. 
Published: February 2015

Abstract
The mesomorphic behavior of N-(4-n-alkylbenzylidene)-4′-n-alkylanilines is investigated and nematic as well as smectic-B phases are found at comparatively low temperatures. Long aliphatic substituents on the aldehyde side of the molecule favor the smectic-B phase. Observations on smectic-B textures, transition enthalpies and density measurements are reported. The simple method used to determine transition temperatures despite impure samples can also be applied to other compounds, e. g. yielding 21.6 - 47.5 °C for the nematic range of MBBA.
Versuche zur Berechnung der 13C chemischen Verschiebung in mesoionischen Verbindungen / Attempts Concerning Calculations of 13C-chemical Shifts in Mesoionic Compounds
Authors: Sterk H. , Thonhofer K. 
Published: February 2015

Abstract
The existence of a linear relationship the form Y=a x1+b x2+c between the charge density - calculated by semiempirical SCF -LCAO -MO-methods - and the 13C -chemical shifts of mesoionic compounds has been shown. An influence of substituents in pyridinium betaines on the chemical shift is not observable.
Reactivity, Equilibrium and Electronegativity
Authors: Hooydonk G. Van 
Published: February 2015

Abstract
The enthalpy ΔH of general displacement reactions
AB + CD AD + CB
is derived with the aid of the ionic approximation to chemical bonding. This enthalpy compares favourably well with Pauling's corresponding equation ΔH= - 46 (xB- xD) (xA - xC)-These ex-pressions are used as a basis to discuss various aspects of chemical reactivity: reversals in reactivity, ambident reactivity, the Hammett relation, the McDaniel-Yingst equation, the Drago E -C equation, the resolution of acid strength, the proton affinities of negative and neutral species and the hard and soft acid-base (HSAB) rule. Qualitatively, and in some cases even quantitatively, reasonable results are obtained, demonstrating the great flexibility of an electronegativity-based theory of chemical reactivity.
Transmission of Electronic Effects in Substituted Pyridine-N-Oxides Studied by ESCA
Authors: Distefano G. , Spunta G. , Colonna F. P. , Pignataro S. 
Published: February 2015

Abstract
Since the first electron spectroscopic (ESCA) studies dealing with substituents effects upon core ionization energies (I.E.) of organic compounds1, little has been published on the subject. This was probably because the reported data did not always seem very meaningful. The absolute I.E. values obtainable in the solid phase are not very certain and also, the "shake-up" phenomena and the consequent broadening of the bands, which affect the I.E. values2, were not always taken into account. None the less we think that ESCA is a valuable tool for the study of substituent effects, and in particular of the transmission of electronic effects in aromatic systems.
Previous work in this area has been published 2,3 , and more specifically an example of steric inhibition of resonance observed by means of ESCA I.E.'s and shake up data was recently reported4. Here we would like to report a further case in which the transmission of electronic effects through an aromatic ring is observed using ESCA.
Ein neues Verfahren zur Präparation von Tantal/Silber und Niob/Silber Tunnel- kontakten / A New Method for the Preparation of Tantalum/Silver and Niobium/Silver Tunneling Contacts
Authors: Gärtner Klaus 
Published: February 2015

Abstract
The preparation starts from material in wire-form. One end of the wire is degassed under ultrahigh-vacuum conditions by a very simple electron-gun and finally melted to form a small smooth sphere. The tunneling barrier is formed by thermal oxidation of the investigated superconductor with oxygen under reduced pressure. The handling of the whole sample (masking and contacting procedures included) is very simple and allows to use this method for systematic tunneling-studies of the transition metal superconductors.
A Determination of Screening Constants for Incomplete Atomic Shells of Elements Z = 2 to 23 from Experimental Ionization Potentials — X-ray Photoelectric Mass Absorption Coefficients for Elements Z = 6 to 15 for 33 Characteristic Energies between 1 and 25 keV
Authors: Stephenson J. D. 
Published: February 2015

Abstract
A method is proposed, which primarily determines screening constants for incomplete atomic shells from the experimental ionization potentials of spin-paired Pauli-type orbitals.
The method is complimentary and in addition to the standard Sommerfeld approach, which derives screening constants from X-ray spin doublet term differences.
Atomic photoelectric absorption cross sections are computed from screened hydrogen-like eigenfunctions for low atomic number elements Z = 6 to 15, using a range of incident photon energies between 1 and 30 keV. Comparison with experiment and alternate more exact theories shows, that improved cross sections are obtained for the more important incomplete L-shell contributions.
X-ray photoelectric mass absorption coefficients for low Z elements (Z= 6 to 15), employing 33 characteristic X-ray energies {NiKα (0.852 keV) to AgKβ (24.942 keV)}, are given.
The von Weizsäcker Coefficient in Density Functional Theoryt
Authors: Meyer A. , Wang Gwo-ching , Young H. 
Published: February 2015

Abstract
For any given potential, linear response theory tells us the size that the von Weizsäcker coefficient must assume in order to obtain the correct energy in the weak coupling limit. With this necessarily imposed choice, the quality of results is investigated as the coupling is strengthened. From the study of a number of model problems (the harmonic oscillator, the Yukawa well and the Mathieu potential) it is concluded that good results can be maintained to high couplings.
Effective g Tensor of a Pair of Dissimilar Ions in the Strong Isotropic Exchange Limit
Authors: Buluggiu E. , Vera A. 
Published: February 2015

Abstract
A study of the spin-pair Hamiltonian with regard to the effective g-factor in the strong isotropic exchange limit is presented. The case of two different spins with anisotropic g(i) and D(i) tensors is considered. Effective gs and Ds tensors for the various total spin S values are deduced in terms of the corresponding single-ion parameters. The characteristics of the resultant gs -tensor, in the case of an ion-pair with Cσ symmetry, are treated in detail. The principal values are linear expressions of the single-ion principal values and the principal directions relative to different 5 values result to be correlated in a characteristic manner. The limits of the present strong exchange treatment are also discussed.
Untersuchungen der Wellenabsorption im Bereich der unteren Hybridresonanz an einem Plasma hoher Ionenmasse / Investigations of Wave Absorption Near the Lower Hybrid Resonance in a Plasma of High Ion Mass
Authors: Lammers B. , Oberlack U. , Schlüter H. , Vogel O. 
Published: February 2015

Abstract
The propagation and absorption of waves in the vicinity of the lower hybrid resonance are investigated under linear conditions in a cesium plasma generated by a Q-machine. The results of the measurements are compared with linear theories based on the fluid model. It is shown that in the case of high ion mass plasma only a theory including a finite k||-spectrum yields an appropriate description of wave absorption near the lower hybrid resonance.
An Inertial Contribution to the Steady State Film Profiles of Viscous Drainage
Authors: Annapurna N. , Ramanaiah G. 
Published: February 2015

Abstract
The effect of inertial terms in the Navier-Stokes equation of viscous drainage on a flat plate is investigated. It is found that they give rise to a constant correction term to the Jeffreys' parabola which persists in the steady state.
Rotationsbarriere der Endgruppen bei Poly- methinoxonolen verschiedener Kettenlänge / Rotation Barrier of the End Groups of Polymethine Oxonols with Different Chain Lengths
Authors: Oehling H. , Baer F. 
Published: February 2015

Abstract
Polymethine oxonols show temperature dependent 1H-NMR-spectra because of restricted rotation of the end groups. The dependence of the value of the corresponding free enthalpy of activation AGt on the length of the poly-methine chain can be explained by the change of the π-electron contribution to ⊿G≠.
Diffusion and Viscous Flow in Ideal Binary Liquid Mixtures
Authors: Haase R. 
Published: February 2015

We discuss the dependence of the diffusion coefficient and
Abstractof the viscosity on the temperature and on the composition for ideal binary liquid mixtures, in particular for the system chlorobenzene + bromobenzene. The activation energy for dif-fusion is independent of the composition and exceeds the activation energy for viscous flow which is a linear function of the mole fractions.
Model for the Interaction of Thermal Radiation with a Monatomic Plasma
Authors: Saraf J. R. 
Published: February 2015

Abstract
A kinetic model for a weakly-ionized plasma interacting with radiation is proposed based on the energy-momentum method, in which both energy and momentum of the system are conserved. The radiation-initiated ionization is obtained in a non-inertial coordinate system, and the proposed model satisfies the H-theorem.
Der Druck bei molekular-dynamischen Simulationen von Ionenflüssigkeiten/ The Pressure in Molecular Dynamics Simulations of Ionic Liquids
Authors: Schäfer L. , Klemm A. 
Published: February 2015

Abstract
Precise molecular dynamics calculations on molten potassium chloride have been performed using Born-Mayer-Huggins pair potentials and periodic boxes containing 216 ions. It is found that the function (2 Ek - ψ)/3V, Ek being the kinetic energy, the instantaneous virial and V the volume, respectively, which on averaging yields the pressure, fluctuates by ± 2000 bar due to the fluctuations of the exponential term ψex of ψ .To base the calculated pressure and velocity auto-correlation functions on good statistics, it seems necessary to reduce these fluctuations by increasing the periodic boxes.
A Theoretical Study on Negative Solvation by Means of Quantum Chemical Calculations on the I(H2O)--Complex
Authors: Rode Bernd M. 
Published: February 2015

Abstract
By means of an “ab initio” all electron treatment of the I-/H2O complex in various geometrical arrangements, it has been attempted to derive some arguments for the general discussion about the phenomenon of negative solvation, based on the background of quantum chemistry. The most stable conformation of the complex is indicated to have C2v symmetry. Rotating of this conformation by 180° leads to an arrangement whose destabilization energy has about the same value as the complex formation energy, which, on the other hand, is only slightly higher than the hydrogen bond energy between two water molecules. These results contradict the formation of an almost rigid first hydration sphere and allow, further, the interpretation of the negative solvation by means of a “cooperative effect” between ion-solvent complex and other solvent molecules, in full agreement with the work of Engel and Hertz.
A New Determination of the π- Rest Mass
Authors: d'Oliveira A. Brandão , Daniel H. , Egidy T. von , Hartmann F. J. 
Published: February 2015

Abstract
The π- rest mass has been determined from measurements of X-ray transitions in pionic atoms, using muonic transitions for the calibration, to be mπ-= 139.571 ± 0.010 MeV. A new upper limit for the μ-neutrino rest mass was deduced: mv<0.78 MeV at 90 per cent confidence.
Multiple Pulse Proton Magnetic Resonance Study of KHCO3 and KHSO4
Authors: Feucht H. , Haeberlen U. , Pollak-Stachura M. , Spieß H. W. 
Published: February 2015

Abstract
Single crystals of KHCO3 and KHSO4 have been investigated by solid state high resolution proton magnetic resonance techniques. These compounds may be considered as model systems for compounds that contain abundant quadrupolar nuclei (39K) with small magnetogyric ratio in ad-dition to the protons. Despite considerable line broadening resulting from 1H-39K dipole-dipole coupling, all four possible proton shielding tensors in KHSO4 , and an averaged shielding tensor for the two different proton sites in KHCO3 could be measured accurately. The results are analysed to determine the degree of ionization of the protons in the three types of hydrogen bonds occuring in KHCO3 and KHSO4.
Some Radiofrequency-Millimeterwave-Double Resonance Experiments, Partly with HFS-levels
Authors: Suzuki M. , Guarnieri A. , Dreizler H. 
Published: February 2015

Abstract
We report double resonance experiments with a broad range of pump frequencies up to 3.9 GHz and millimeter wave signal frequencies up to 160 GHz. It is demonstrated by the HFS of a rotational band head that these experiments provide a useful tool for analysing complex spectra in the range below 4 GHz.
The Molecular Zeeman-Effect in 1,3-Difluorobenzene and 3-Methylfurane
Authors: Czieslik W. , Wiese J. , Sutter D. H. 
Published: February 2015

Abstract
The rotational Zeeman effect of 1,3-difluorobenzene and 3-methylfurane has been studied at magnetic fields close to 25 kG. From the splittings of the rotational transitions the diagonal elements of the molecular g-tensors and the anisotropics of the diagonal elements of the magnetic susceptibility tensors have been determined as:
gaa=-0.0486±'0.0002, gbb = -0.0315 + 0.0003, gcc = +0.0116±0.0003,
(2 Xaa-Xbb-Xcc)NL = (46.6 ± 0.4) · 10-6 erg/ (G2 mole),
(2 Xbb-Xcc-Zaa)NL = (55.7 ± 0.4) · 10-6 erg/(G2 mole)
for 1,3-difluorobenzene and as
gaa = -0.0716 + 0.0006, gbb = -0.0370±0.0003, gcc =0.0222±0.0003,
(2 Xaa-Xbb-Xcc)NL = (25.7 ± 0.6) · 10-6 erg/(G2 mole),
(2 Xbb-Xcc-Xaa)NL = (43.1 ±0.5) · 10-6 erg/(G2 mole)
for 3-methylfurane. From comparison with related compounds position dependent substitution effects on the susceptibility anisotropics become appearent. The scheme of local atom susceptibilities is extended to fluorine containing molecules.
Site Selection Spectroscopy in the Temperature Range 2 K and 300 K
Authors: Fiatscher G. , Fritz K. , Friedrich J. 
Published: February 2015

Abstract
In this paper we show that there exist rather simple aromatic systems which show no line narrowing in their fluorescence at 2 K, when excited with narrow bandwidth. However, large inhomogeneous line broadening is detected via a shift of the fluorescence bands with excitation energy. This inhomogenous broadening is attributed to a quasi-continuous site splitting, which is present up to about 240 K. The influence of high excess energy on the inhomogenous broadening is dis-cussed.
Intensity Ratios within the Balmer Lines Hα and Hβ After Dissociative Excitation of C6H6 and H2
Authors: Hartfuß H. J. , Neumann J. , Schneider H. D. 
Published: February 2015

Abstract
The decay-curves of the Balmer-lines Hα and Hβ have been measured after dissociative excitation of C6H6 and H2 by electron-impact in the 100 eV range. The analysis of the decay-curves shows, in agreement with other authors, that only the 3s-and 3d-states in the case of Hα and the 4s-and 4d-states in the case of Hβ contribute significantly to the total intensity of Hα and Hβ, respectively, but not the p-states 3p and 4p.
The intensity-ratios J(3s)/J(Ha) and J(4s)/J(Hβ) have been investigated. Comparison with the total emission cross-sections of the states n=3 and n=4 allows to determine the excitation cross-sections of the sublevels 3s and 4s. It is found that s-state production is favoured in the dissocia-tion process. This seems to be independent on the principal quantum number.
Dissoziation von H2
+ und H3
+ beim Stoß an Kr im Energiebereich 6 – 60 keV / Dissociation of H2
+ and H3
+ by Collision with Kr in the Energy Range between 6 to 60 keV
Authors: Lehmann B. 
Published: February 2015

Abstract
H2
+ and H3
+ ions, produced in a H2 plasma of a radio-frequency ion source, were accelerated to 6-60 keV and directed into a gas target of Krypton. The cross sections for the formation of H+ and H- resp. H2
+, H+ and H- have been measured. In the case of H+, obtained from the dissociation of H2
+, 2 maxima have been found in the present energy range. A third is known to be at about 100 keV. We discuss the applicability of the Massey' adiabatic hypothesis, known from the analysis of charge-exchange experiments, to the maxima in the cross-section vs. energy curve for dissociation experiments.
Three-Dimensional Electron Microscopy of Individual Biological Objects Part II. Test Calculations
Authors: Hoppe W. , Schramm H. J. , Sturm M. , Hunsmann N. , Gaßmann J. 
Published: February 2015

Abstract
In this second part of the paper the general conclusions of part I with regard to resolution and image point shape, variable boundaries of the projected three-dimensional body and origin definition have been tested by computer simulations. The influence of clutter and noise has been discussed.
Top-Top Interaction in Hexa-Deutero Dimethyl Selenide from the Microwave Spectrum in the First Excited Torsional States
Authors: Pandey G. K. , Lutz H. , Dreizler H. 
Published: February 2015

Abstract
An analysis of the internal rotation fine structure for the rotational transitions of hexa-deutero dimethyl selenide in the first excited torsional states is presented in terms of a molecular model with two degrees of freedom for the internal rotation or torsion of the two tops in addition to the three degrees of freedom for the overall rotation. By a least squares fit of the multiplet splittings of ten transitions in the vn=11 and nine transitions in the ṽn=12 excited torsional states, the following parameters have been obtained: F3=1493±9 cal mol-1; ϑ=50°1′±7′ V12′=28.4±0.3 cal mol-1. The splitting of the fine structure components could be nicely fitted, but not their absolute frequencies and the seperation between the two multiplets.
Pre-and Post-Transitional Behavior of the Flow Alignment and Flow-Induced Phase Transition in Liquid Crystals
Authors: Hess Siegfried 
Published: February 2015

Abstract
The flow alignment in the isotropic and nematic phases of a liquid crystal is studied theoretically with special emphasis on temperatures close to the transition temperature. The point of departure is a nonlinear, inhomogeneous relaxation equation for the alignment tensor which is applicable to both phases. The stationary solutions of this equation are analysed. In addition to some well-known results which are recovered as limiting cases for small velocity gradients, it is found that a sufficiently large velocity gradient can induce a transition into an ordered phase if the temperature is between the transition temperature for equilibrium conditions and a somewhat larger critical temperature. In the nematic phase, a weak dependence of the flow alignment angle on the magnitude of the velocity gradient is obtained. The relaxation towards a steady state is also considered.