bluuebunny/crossref_metadata_2025 huggingface dataset:
Miscibility Gaps in Fused Salts Note VIII. Mixtures Formed by LiF and two Alkali Bromides
Authors: Flor G. , Margheritis Ch. , Sinistri C.
Published: February 2015

Demixing phenomena were studied in 12 mixtures type LiF + (MeI, MeII)Br, MeI and MeII being alkali metals. Previous measurements of the LL equilibria in the system LiF + CsBr were extended to the high temperature field to evaluate the position of the point of maximum. Moreover, the data obtained on the system LiF + NaBr were analyzed in order to calculate the critical temperature of the "submerged" gap. The results allowed to test the thermodynamic theories concerning the reciprocal ternary systems in the case of large deviations from ideality.
Hyperschalleigenschaften von Wasser-Äthanolmischungen
Authors: Asenbaum A. , Sedlacek M.
Published: February 2015

In water-ethanol mixtures hypersound velocities and hypersound damping were measured at 10°, 20°, and 25 °C by Brillouin scattering. From the experimental data the relaxation frequency and the noerelaxing fraction of the bulk viscosity were calculated.
Multipole Polarizabilities from Hartree-Fock Densities by Statistical Perturbation Theory, a Semiempirical Approach
Authors: Witschel W. , Haars J.
Published: February 2015

A statistical variation-perturbation method is used in the derivation of multipole polarizabilities from Hartree-Fock electron densities. A quantum correction of the kinetic energy expressions takes into account the exponential decrease of the electron density in the outer part of the atom. The method is called semiempirical because of the still unsolved problem of the kinetic energy in the statistical theory of the atom. The results are compared to the best available experimental and theoretical values of dipole-and quadrupole-polarizabilities and show agreement within approxi-mately 10 - 15 percent. They are lower than Hartree-Fock perturbation results. As the numerical calculations are reduced to single integrations, the mathematical labor is considerably reduced. In an appendix dipole polarizabilities are calculated in the framework of the Gombas model including exchange and correlation for ionization degrees from zero to six.
Interferometric Mode Selector for a cw Dye Ring Laser
Authors: Marowsky G. , Stuke M.
Published: February 2015

A novel interferometric mode selector allows easy alignment and stable operation of a cw dye ring laser. Details of its function in multimode and single mode operation are described.
Density and Compressibility of Liquid Li-Pb Alloys
Authors: Ruppersberg Henner , Speicher Walter
Published: February 2015

The density and the velocity of sound of liquid Li-Pb alloys have been measured in the composition ranges 0 - 17, 30 - 100 at % Pb and 0-10, 40 - 100 at % Pb, respectively. The temperature dependence of these properties has been determined for each sample in a temperature range of at least 130 K. The excess volume is negative and has a minimum at about 20at%Pb, where the volume per atom at 800 °C is about 19% smaller than the volume of an ideal solution. The absolute value of the excess volume rises with the temperature, as does the absolute value of the deviation of the adiabatic compressibility from the mean compressibility.
Deuterium Isotope Effect in the Radiative Triplet Decay of Heavy Atom Substituted Aromatic Molecules
Authors: Friedrich J. , Vogel J. , Windhager W. , Dörr F.
Published: February 2015

We studied the effect of deuteration on the radiative decay of the triplet sublevels of naphthalene and some halogenated derivatives. We found that the influence of deuteration is much more pronounced in the heavy atom substituted than in the parent hydrocarbons. The strongest change upon deuteration is in the radiative decay of the out-of-plane polarized spin state Tx . These findings are consistently related to a second order Herzberg-Teller (HT) spin-orbit coupling. Though we found only a small influence of deuteration on the total radiative rate in naphthalene, a significantly larger effect is observed in the rate of the 00-transition of the phosphorescence. This result is discussed in terms of a change of the overlap integral of the vibrational groundstates of T1 and S0 upon deuteration.
Struktur von Schmelzen aus dem System Wismut-Antimon mittels Neutronenbeugung
Authors: Lamparter Peter , Steeb Siegfried , Knoll Walter
Published: February 2015

Neutron diffraction work (λ = 0.695 Å) was done with molten Bi-Sb-alloys in the temperature range between 550 and 750 °C. Furthermore molten Bi was investigated at 300 °C. The interference functions show subsidiary maxima especially for alloys with higher Sb-concentrations. Evaluation yields, that the melts contain two different kinds of structure:

a) The one kind shows coordination number 9 and a statistical distribution of the atoms of two components. This kind is more inetal-like.

b) The other kind shows coordination number 3, consists of non-centered tetrahedra with smaller nearest neighbour distance. It shows covalent binding.

In molten Sb the nearest neighbour distance amounts up to 3.16 - 3.19 Å for theo ne kind and up to 2.64 -2.78 Å fort he other kind, which yields an mean distance of 2.99 Å, which was observed. The dependence of the concentration of the statistical kind of meld, of the (Sb)4-, and the (Bi)4-kind from the concentration of the whole melt is given.

By the model described the run of the measured mean coordination number and the mean distance versus concentration can be well explained.
Evidence for Preferential Polymer Solvation from Time-resolved Rayleigh Light Scattering Measurements
Authors: Dobrowolski G. , Schnabel W.
Published: February 2015

In an acetone solution containing small portions of naphthalene the latter is adsorbed preferentially to poly(methylmethacrylate- co-phenylvinylketone). Evidence for preferential solvation is inferred from intrinsic viscosity data as well as from the halflife of the change of light scattering intensity after fragmentation of the macromolecules by a 25 ns flash of 347 nm light from a ruby laser.
Comments on Quartic Centrifugal Distortion Constants for Asymmetric Top Molecules
Authors: Yamada Koichi , Winnewisser Manfred
Published: February 2015

Explicit relations between the spectroscopic constants, A͂ , B͂ , C͂, ⊿J,⊿JK, ⊿K, δJ,and δK,

obtained by the application of the various reduction procedures of the effective rotational Hamil­tonian are given in matrix formulation. Watson’s reduction procedures for the three different axis representations Ir, IIr, and IIIr have been considered as well as the reduction making R͂5 = 0, in­stead of R͂6 = 0.

The ambiguity in the determination of the τ’s arising from the use of planarity conditions is discussed in relation to the τ defect.
The Absorption Spectrum of Isotopic Diatomic Antimony ( 123Sb-123Sb). Analysis of the D ← X System in the 2860—2920 Å Region
Authors: Sibai Abdel Mooti , Topouzkhanian Ari , Perdigon Pierre
Published: February 2015

A rotational analysis of several bands of the D←X system of 123Sb−123Sb is carried out. It is shown that the hitherto assumed vibrational classification of the D←X system is certainly incorrect, as well as a previously given value for the rotational constant of the X state. B(X1∑g
+, ν=0) is found equal to 0.044263 cm-1. The perturbations appearing in the various vibrational levels are interpreted in terms of interactions with a new electronic state, labelled L.
Zum Verlauf der Gastemperatur in einer unipolaren Argon-HF-Entladung
Authors: Fischer Dieter
Published: February 2015

Temperature The temperature of the neutral gas (TGas) in an unipolar HF-discharge excited in argon at atmospheric pressure is measured by Mach-Zehnder-interferences. This value of the temperature can be compared with theoretical results concerning the relation between TGas, Trot and Te in dependence of the electron density Ne.
Electron Spectroscopic Studies of the Oxidation of Ni/Pd Alloys
Authors: Wandelt K. , Ertl G.
Published: February 2015

The oxidation of polycrystalline samples of Ni/Pd-alloys at 600 °C and 2·10-5 Torr O2 has been investigated by means of Auger electron spectroscopy and soft x-ray appearance potential spectroscopy. The clean surfaces are enriched by Pd; and with increasing Pd content the binding energy of the Ni 2p-core levels was found to decrease continuously by 0.7 eV. After completion of the oxidation identical overlayers were formed on all samples (except on pure Pd!) which were identified to consist of NiO. Within the depth probed by the applied techniques (≲20 Å) the rate of oxidation was found to increase with increasing Pd content, which is in contrast to the behaviour to be expected for the growth of thick oxide layers after the formation of a coherent NiO overlayer.
Sondheimer-und Durchbruch-Oszillationen in Aluminium / Sondheimer and Magnetic Breakdown Oscillations in AI
Authors: Papastaikoudis Constantin
Published: February 2015

The electrical resistivity of thin single crystal aluminium samples has been measured in a transverse magnetic field at 4.2 K. The magnetoresistance shows Sondheimer and mag-netic breakdown oscillations.
Energies of Trivalent Cation Impurity-Cation Vacancy Complexes in KCl
Authors: Shukla A. K. , Uppal M. K.
Published: February 2015

Interaction energies of six trivalent cation impurity-cation vacancy configurations in KCl have been evaluated and compared with experimental data.
Dielektrische Relaxation und Elektronenspinrelaxation von Eisen(III)acetylacetonat in verdünnter Lösung/ Dielectric Relaxation and Electron Spin Relaxation of Ferric Acetylacetonate in Dilute Solutions
Authors: Dietz W. , Kilp H. , Noerpel W. , Straßmann M. , Stockhausen M.
Published: February 2015

The dielectric loss and electron spin resonance linewidth of ferric acetylacetonate have been measured in dilute solutions of benzene, m-and p-xylene, mesitylene and carbon tetrachloride. Permittivity measurements were made at 10 frequencies in the microwave region (1.2 m to 1 mm wave-length), ESR measurement at 2 frequencies (X and Q band). The permittivity results show a broad non-Debye pattern, yielding a mean correlation time of about 4 ps. The ESR results yield a mean correlation time of about 3 ps. The parallelism between the results obtained by both methods is discussed in view of a common relaxation process, which is the transient deformation of the chelate system resulting from stochastic induction by neighbouring solvent molecules.
A Molecular Dynamics Study of Aqueous Solutions
Authors: Vogel P. C. , Heinzinger K.
Published: February 2015

Results of a molecular dynamics study of a 0.55 molal aqueous NaCl solution are reported. The basic periodic box contained 200 water molecules, 2 sodium ions and 2 chloride ions. The calculated properties of this solution are compared with those obtained previously for a 2.2 molal NaCl solution. The formation of second hydration shells, an increase of the number of water molecules in the first hydration shells, and a release of internal pressure are the main changes connected with a decrease of the concentration.
The Role of the Oceans as a Sink for Chlorofluormethanes and similar Compounds
Authors: Junge C.
Published: February 2015

Model calculations show that the oceans do not represent a global sink for chlorofluoromethanes (CFM 11 and 12) of any significance. The amount absorbed by the oceans consists essentially of three portions: The portion dissolved in the mixing layer; the one that enters the deep sea and the portion which is decomposed or disappears otherwise within the mixing layer by chemical or biological processes. The calculations show that the total amount of CFM which may have entered the oceans up to the present time cannot have exceeded a few percent even if high destruction rates would occur in the oceans. Solubility data in ocean water in conjunction with concentration data in the oceans indicate, however, that the net destruction rate of CFM 11 in the oceans is only of the order of 10-7 sec-1 .
The Configuration of Organic Carbanions
Authors: Shanshal Muthana
Published: February 2015

The configurations of organic carbanions are studied using the MINDO/1 and MINDO/2 methods. It is found that the stability of the pyramidal configuration increases on going to small ring cyclic carbanions. Conjugation to an olefinic group decreases the inversion barriers of pyramidal carbanions but does not lead to their planarization. Conjugation to a nitro group, however, causes the planarization of the carbanions. It is found that the monosolvation of methylcarbanion increases its planarization energy.
Notizen:The Occurrence of Ultrastrong Magnetic Fields in Nuclear Shock Waves
Authors: Winterberg F.
Published: February 2015

In fast heavy nucleus-nucleus collisions transient magnetic fields as high as ~1018 Gauss are predicted. The occurrence of these superstrong magnetic fields may lead to the production of magnetic monopoles and to CP conservation with zero Cabibbo angle.
Der Gültigkeitsbereich der Molièreschen Näherung/ The Range of Validity of the Molière Approximation
Authors: Lehmann H. , Schoenebeck H.
Published: February 2015

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

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.
O(4)-Symmetrie und Stark-Effekt des H-Atoms / O(4)-Symmetry and Stark-Effect of the H-Atom
Authors: Becker H. G. , Bleuler K.
Published: February 2015

Using the advantages of the O (4)-symmetry the second order Stark-effect of the hydrogen atom is calculated by the Dalgarno-Lewis perturbation method in a purely algebraic manner. The Starkeffect provides the first quantum mechanical example in which the Dalgarno-Lewis equation relevant for second and third order perturbation theory of the whole spectrum can be exactly solved
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
Die Stärke der antiferromagnetischen Kopplung in Gallium-dotiertem α-Cr2O3 / The Intensity of the Antiferromagnetic Coupling in Gallium-doped, α-Cr2O3
Authors: Dräger K.
Published: February 2015

ESR-spectra of the mixed system (1-x) Cr2O3 • x Ga2O3 having a concentration depending Neeltemperature TN are thoroughly investigated. For polycristalline samples with concentrations up to 6% it is shown that the line shape of the absorption curves has Lorentzian character in the whole temperature range. Within a mean variation of 0,8% and for T>TN, the temperature dependence of the ESR-intensity confirmes the proposed cluster-model. While pure Cr2O3 has a coupling energy of ΔE = 430 cm-1, this value reduces slowly by the incorporation of Ga3+-ions. At a concentration of x = 6% the reduction amounts to about 9%. As all spins exhibit a uniform behaviour, one evidently can calculate the exchange constant J12 for nearest neighbours interaction even in the Gallium-doped crystal
Measurement of PVT Data for Molten Potassium Chloride to 1320K and 6 kbar
Authors: Goldmann G. , Tödheide K.
Published: February 2015

PVT data of molten KCl as a typical example for an ionic melt have been measured between 770 and 1050 °C at pressures up to 6 kbar. The experiments were performed in an internally heated pressure vessel containing argon as pressure transmitting medium. The salt was enclosed in a stainless steel cell the volume of which could be varied by means of a metal bellows and measured by monitoring the displacement of one end of the cell using an inductive transducer. The accuracy of the density data obtained is 0.15% for pressures below 2 kbar and 0.4% for higher pressures
Proton Spin-Rotational Interaction in Crystalline 1-Hydroxy-2,4-Hexadiyne
Authors: Schütz J. U. von , Bloor D. , Steudle W. , Wolf H. C. , Ando D. J.
Published: February 2015

The amplitude and temperature dependence of the longitudinal proton spin relaxation time T1 in crystalline 1-hydroxy-2,4-hexadiyne is caused by the activated process of the CH3-group reorientation. The low hindering barrier of 4.4 kj/mole leads above 200 K to relaxation contributions by spin-rotational interaction, which are comparable to the dipolar interaction
Laserspektroskopische Untersuchungen an nicht-stabilisierten N2(B3IIg, ν; = 13)-Molekülen / Laser Spectroscopic Studies on Non-stabilized N2(B3IIg, ν; = 13) molecules
Authors: Becker K. H. , Engels H. , Tatarczyk T.
Published: February 2015

Unstabilized N2(B3IIg, ν = 13) quasi-molecules were analysed by excitation with a tunable dye-laser into the N2(C3IIu) state and observation of the following fluorescence to N2(B3IIg, ν) levels. The quasi-molecules are in equilibrium with the free nitrogen atoms. The detection limit of this technique is 105 molecules/cm3. By the same method, a rotational analysis of molecules stabilized into (B3IIg, ν ≦ 12) levels by three-body recombination processes was achieved with a resolution better than that reached by emission spectroscopy of the Lewis-Rayleigh afterglow
Consequences of Restricted Defect Diffusion on NMR and Dielectric Relaxation
Authors: Kimmich R.
Published: February 2015

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
Thermal Instability of a Compressible Hall Plasma
Authors: Sharma R. C.
Published: February 2015

The thermal instability of a Hall plasma taking compressibility into account is studied. The effect of compressibility is found to be stabilizing while the Hall currents have a destabilizing effect. The system is stable for (cp/g)β<1. Oscillatory modes are introduced due to the presence of a magnetic field which are missing in the absence of a magnetic field (and hence in the absence of Hall currents) for (cp/g)β > 1. The case of overstability is also discussed.
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

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

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

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

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

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

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

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

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

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

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

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

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

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.
A Model for Spin-lattice Relaxation in Metals
Authors: Koppe H. , Schattke W.
Published: February 2015

The electromagnetic fields of the ions moving in a sound wave give rise to an interaction of electron spins with trans-verse phonons. The lifetime of a spin is calculated in lowest perturbational order.
Pre-and Post-Transitional Behavior of the Flow Alignment and Flow-Induced Phase Transition in Liquid Crystals
Authors: Hess Siegfried
Published: February 2015

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.
Decomposition of Viscosity Tensors for Gyrotropic Media
Authors: Sturhann Ursula , Suchy Kurt
Published: February 2015

For a medium whose anisotropy is caused by a physical quantity expressed by an axial vector, e. g. an ambient magnetic field, the viscosity tensor has 8 independent components and is consequently decomposed in 8 terms. One term, multiplied with the bulk viscosity, connects the traces of the viscous pressure tensor and the velocity gradient, while traces and tracefree parts of these two tensors are coupled by two other terms, whose coefficients are required to be equal by Onsager's symmetry relations. The remaining 5 terms are represented by generalized Hess-Waldmann projectors. The corresponding 5 viscosity coefficients are related to those introduced by Braginskii, de Groot-Mazur, and Hess-Waldmann.
Lineare Welleneinkopplung in ein Plasma erhöhter Elektronen- Temperatur bei der unteren Hybridresonanz / Linear Wave Coupling to a Plasma of Enhanced Electron Temperature at the Lower Hybrid Resonance
Authors: Glomski G. , Heinrich B. , Schlüter H.
Published: February 2015

Linear Wave Coupling to a Plasma of Enhanced Electron Temperature at the Lower Hybrid Resonance Radio frequency waves in the range of the lower hybrid resonance are coupled to a plasma of enhanced electron temperature (≈ 106 K) and reduced collision frequency (≈ 7 · 105 s-1). The experiment demonstrates the persistance of resonance behavior even under this conditions. Radial eigenmodes are dominant, but exhibit - as compared to linear theoretical models - additional damping with an effective collision frequency in the order of 3 · 107
s-1. For the conditions considered this effect is attributable to Landau damping.
Einfluß von Spiegelanordnungen bei der unteren Hybridresonanz / The Influence of Mirror Configurations Near the Lower Hybrid Resonance
Authors: Glomski G. , Heinrich B. , Schlüter H.
Published: February 2015

The Influence of Mirror Configurations Near the Lower Hybrid. Resonance Hydrogen plasmas in magnetic mirror configurations are generated by microwaves and inductively coupled to a weak rf-source. In contrast to previous investigations the rf-frequency is varied; resonant behaviour near the lower hybrid frequency is found, attributable to radial eigenmodes. The influence of various mirror ratios and consequently varying axial density gradients on the position of the modes is studied. Shifts of the coupling coil are found to be of minor importance, since the resonant behaviour is dominated by oscillations of the whole plasma body.
Nichtlineare Welleneinkopplung in ein Plasma erhöhter Elektronentemperatur / Nonlinear Wave Coupling to a Plasma of Enhanced Electron Temperature
Authors: Glomski G. , Heinrich B. , Schlüter H.
Published: February 2015

Nonlinear Wave Coupling to a Plasma of Enhanced Electron Temperature In continuation of former investigations radio waves of different amplitude in the domain of lower hybrid resonance were coupled to a plasma of enhanced electron temperature. Under linear conditions no dependence of resonance behaviour on the wave amplitude was observed. Exceeding a treshhold maximum of absorption and electron density decreased significantly; both observations may be explained by onset of nonlinear and parametric effects. Increasing the amplitude the discharge only could be maintained by increasing the neutral gas pressure. In the power range of 15 to 20 kW electron density grew rapidly at resonance.
Symmetry Coordinates and Tentative Force Field Analysis of a PMo12O40 Model with the Keggin Structure
Authors: Lyhamn Lennart , Cyvin S. J. , Cyvin B. N. , Brunvoll J.
Published: February 2015

A complete vibrational analysis is performed for the 53 atomic PMo12O40 model of Td symmetry. The symmetry coordinates are classified into those of (a) ligand vibrations, (b) framework-ligand couplings, (c) framework vibrations, and (d) interligand vibrations. Simple valence force fields are estimated, and the influence of inclusion of redundancies on the calculated frequencies and symmetry force constants is investigated. Comments are made on calculated symmetry force constant values up to 345 mdyne/Å. Vibrational frequencies are calculated for the Mo3O7 and Mo3O13 units and for the PMo12O40
3- complex ion. For the latter compound the calculated values are compared with experimental data from infrared and Raman spectra.
Nachweis einer antiparallelen Spinkopplung in paramagnetischem Manganoxid / Proof of Antiparallel Spin-Coupling in Paramagnetic Manganese Oxid
Authors: Dräger K. , Kratz G.
Published: February 2015

For temperatures above the Néel-point it is shown that there are severe deviations from pure paramagnetism in the ESR-behaviour of stoechiometric MnO. The experimental results in the temperature range between 130 K and 480 K are interpreted by a model of local order. The excitation energy necessary to decouple the antiferromagnetic bonding is computed to be about ΔE= 250 ± 15 cm-1 . For a temperature of T=TN +10 we derive that according to this theory 73% of all spins in MnO still remain in antiparallel order.

Further calculations show that the bonding is compatible with an isotropic exchange interaction of next nearest neighbours having a coupling constant of J2 = 3.42 K. Finally, an interesting aspect is discussed connecting the formation of antiferromagnetic clusters and the absorption behaviour of MnO in the far infrared.
Ultrasound Absorption in Trifluoroacetic Acid and its Equimolar Mixture with Acetic Acid
Authors: Mang H. , Kohler Friedrich
Published: February 2015

Ultrasound absorption has been measured in pure trifluoroacetic acid and its approximately equimolar mixture with acetic acid (51.5 mole% of acetic acid) at 20, 30, 40, and 50 °C and atmospheric pressure over the frequency range 3 - 57 MHz. The absorption curve of trifluoroacetic acid could be flitted by a single relaxation step (relaxation frequency 3.5 - 11 MHz, low frequency absorption about one tenth of that of acetic acid), whereas the equimolar mixture followed a two step relaxation curve (lower relaxation frequency 1.5 - 3 MHz, absorption correspondingly higher than in pure trifluoroacetic acid, higher relaxation frequency 12.5 - 39 MHz, absorption about 3% of the low frequency absorption).
Gas Supersaturation Thresholds for Spontaneous Cavitation in Water with Gas Equilibration Pressures up to 570 atm1
Authors: Gerth Wayne A. , Hemmingsen Edvard A.
Published: February 2015

Supersaturations for the onset of cavitation in water were determined for various gases. At ambient pressure, the threshold supersaturations (in atm) required for profuse cavitation to initiate both in bulk water and at the glass-water interface were CH4, 120; Ar, 160; N2, 190; He, 360. Exposure of the water and its containing surfaces to hydrostatic pressures up to 1100 atm prior to equilibration with gas had no detectable effect on these threshold values. This indicates that preformed gas nuclei are not significantly involved. Cavitation at the glass-water interface was investigated for CH4, Ar and N2 saturations up to 570 atm. For 320 atm saturations, the threshold super-saturation was about one-half that for decompression directly to ambient pressure, and for 550 atm it was about one-third. These results indicate that the dissolved gas concentration is a critical factor limiting the spontaneous nucleation of bubbles in gas supersaturated liquids.