bluuebunny/crossref_metadata_2025 huggingface dataset:
An Approximate Treatment of the 1s Hartree Fock Energies in Molecules
Authors: Shanshal Muthana
Published: February 2015

It is found on the basis of Hartree Fock calculations that the inner shell molecular orbitals of compounds that are composed of elements of the first two rows of the periodic table, are described satisfactorily by the corresponding Is atomic orbitals. Such molecular orbitals (MOs) may be substituted in a good approximation by the Is atomic orbitals (AOs). The energy of the localized MOs varies according to the type of bonding in which the atom is participating. The factors influencing the energy values may be classified in two parts; 1) the interaction with the other Is atomic orbitals and nuclii in the molecule, 2) the interaction with the valence shell electrons. Neglecting the correlation effects, both factors are considered by the calculation of the Is orbital energies. The results are compared with ab-Initio calculations done for the same molecules.
O n an Ionic Approximation to Chemical Bonding
Authors: Hooydonk G. Van
Published: February 2015

It is shown how previously reported bond energy equations (Van Hooydonk, 1973) can be regenerated starting from the assumptions (i) that the valence-orbital energy of an element in a bond can be expressed as a function of its occupancy number (Iczkowski-Margrave, 1961) and (ii) that the potential around an atom in a bond vanishes as soon as its valence orbital is doubly occupied (Ferreira, 1963). The results are consistent with an ionic approximation to chemical bonding. A comparison of the approximations involved in the present theory with those in a semi-empirical LCAO -MO method (Klopman, 1964) is advanced.
Der Zeeman-Effekt im Rotationsspektrum von Orthodifluorbenzol
Authors: Sutter Dieter H.
Published: February 2015

The linear and quadratic rotational Zeeman effect in orthodifluorobenzene has been observed in magnetic fields up to 25 kG. The magnetic susceptibility anisotropies are χaa- (χbb -χcc)/2 = (25.4 ± 0.8)* 10-6 erg/(G2 * mole) and χbb - (χcc - χaa)/2 = (29.0±0.5)* 10-6 erg/ (G2 * mole) ; (the c-axis is perpendicular to the molecular plane and the a-axis coincides with the twofold symmetry axis of the molecule); the molecular ^-values are gaa= -0.0412 ± 0.00'I2, gbb=0.0371± 0.0008 and gcc= +0.0163 ±0.0007. A comparison of ⊿χ = χcc- (χaa + χbb)/2 with the corresponding values of related compounds, part of which were determined by the Cotton-Mouton technique, indicates that the effect of the magnetic field on the electric polarizability of benzene - like molecules is in the order of - 1 * 10-39 cm3/G2 and should be accounted for in the evaluation of Cotton- Mouton data.
Torsions-Vibrations-Rotations-Wechselwirkung im Mikrowellenspektrum von Methylthiocyanat
Authors: Andresen U. , Dreizier H.
Published: February 2015

The microwave spectrum of methylthiocyanate is reinvestigated on the basis of a molecular model with five degrees of freedom, three for the overall rotation, one for the torsion and one for another vibration. It was possible to fit the splittings of all four measured states (ground state, first excited torsional and vibrational state and second excited vibrational state) with one set of parameters but it was impossible to fit the absolute line frequencies. The value for the potential parameter of the pure torsion V3 is in good agreement with that determined on the basis of the rigid framerigid top (RF-RT) model from the ground state.
Ab-initio Calculation on Methylnitrenium Ion (CH3NH)+
Authors: Gunde R. , Ažman A.
Published: February 2015

Ab initio calculation were carried out on the singlet and triplet states of the methylnitrenium ion. The triplet state is the ground state for all values of angle at nitrogen.
On the Hydromagnetic Kelvin-Helmholtz Instability between Compressible Fluids
Authors: Srivastava K. M.
Published: February 2015

We have discussed the effect of gravity on the hydromagnetic Kelvin-Helmholtz instability of a plane interface between compressible, inviscid, infinitely conducting fluids. The stability of the interface is investigated including gravity. The solar plasma and the magnetospheric medium are supposed to be of equal density and to carry a uniform magnetic field (H ) in the direction of streaming. The cases (i) H1 ≠ H2 and x1 (x = cp/cv) not necessarily equal to x2 , (ii) H1= H2 x1 ≠ x2 and (iii) H1 = H2, x1=x2 are discussed for perturbations, transverse as well as parallel to the direction of streaming. It is concluded that the interface is unstable in all the cases except for transverse perturbations, the two media carrying the same magnetic field and being characterized by the same x, when it is found to be verlocity.
Dielectric Constants and Molecular Structure of Nematic Liquid Crystals
Authors: de Jeu W. H. , Lathouwers Th. W.
Published: February 2015

Measurements are presented of the dielectric constants of some p,p′-n-alyl and n-alkoxy substituted azobenzenes and azoxybenzenes in the nematic and in the isotropic phase. Starting from the dipole-less, p,p′,di-n-alkyl-azobenzenes, a systematic interpretation is given of the influence of the molecular structure on the dielectric properties.
Isotopic Mineral Ages of a Diorite from the Eisenkappel Intrusion, Austria
Authors: Lippolt Hans J. , Pidgeon Robert
Published: February 2015

40K-40Ar ages on biotite (227±7 m.y.) and hornblende (244±8 m.y.) and a 238U-208Pb age on sphene (230±5 m.y.) were determined for a diorite from the Eisenkappel intrusion from Southern Carinthia in Austria. The intrusion is stratigraphically dated at younger than Lower Carboniferous. The isotopic results suggest the diorite was emplaced between the Upper Permian and the Lower Triassic.
On the Thermochemical and Electrochemical Series of Elements
Authors: Hooydonk G. van
Published: February 2015

Standard electrode potentials of elements are compared with the electronegativity values (or electron affinities), proposed earlier. It is concluded that chemical interactions are the result of the oxidising character of elements, in agreement with an ionic approximation to chemical bonding.
Three and Four Centre Oscillators and Their Application in Nuclear Physics
Authors: Bergmann Peter , Scheefer Hans-Joachim
Published: February 2015

The extension of the nuclear two-centre-oscillator to three and four centres is investigated. Some special symmetry-properties are required. In two cases an analytical solution of the Schrödinger equation is possible. A numerical procedure is developed which enables the diagonalization of the Hamiltonian in a non-orthogonal basis without applying Schmidt's method of orthonormalization. This is important for calculations of arbitrary two-dimensional arrangements of the centres.
Zu Stofftransport und Hydrodynamik der Pulsationsdiffusion
Authors: Beßerdich H. , Kahrig E. , Lange Fr.
Published: February 2015

Investigating experimentally the frequency dependence of the diffusion transport and the flow stability by hot-wire experiments within the pulsation capillary and comparing the results with the general treatment (see part I) it can be stated that in parameter ranges which are important for the practical application a good coincidence exists. Deviations between theory and experiment observed under extreme conditions are discussed.
Photolumineszenz und Radiothermolumineszenz an CaWO4 - und CaWO4 :Pb-Einkristallen / Photoluminescence and Radiothermoluminescence of CaWO4- and CaWO4: Pb single crystals
Authors: Becker M. , Scharmann A.
Published: February 2015

Luminescence spectra, absorption spectra, thermoluminescence, and thermally stimulated conductivity after irradiation with X-rays of CaWO4 - and CaWO4 : Pb single crystals were investigated in the temperature range from 4,2 to 300 K. The relations between thermoluminescence and luminescence properties are discussed.
Das Temperaturverhalten der Protonenresonanz von adsorbiertem Benzol in den Hohlräumen synthetischer Zeolithe vom Typ des Faujasits / The Temperature Behaviour of the Proton Resonance of Adsorbed Benzene in the Holes of Synthetic Zeolites of the Faujasite-Type
Authors: Lechert Hans , Hennig Heinz-Jürgen
Published: February 2015

In the present paper, the behaviour of the proton magnetic resonance of adsorbed benzene in the holes of two faujasite samples with different Si/Al-ratios is measured. The second moments at low temperatures give evidence that at low coverages the adsorbed molecules rotate about an axis in the plane of the molecules. At coverages above 4,5 benzene molecules in a large cavity, this rotation is hindered. At higher temperatures an additional mobility is observed in the resonance spectra, which seems to consist of jumps between the sorption sites of the molecules of the benzene.
Kinetic Theory of Flow Birefringence in Dilute Gases of Symmetric Top Molecules
Authors: Hess S.
Published: February 2015

Flow birefringence in dilute gases of symmetric top molecules is treated within the framework of the kinetic theory based on the Waldmann-Snider equation. A microscopic expression is derived for the characteristic flow birefringence coefficient. Its magnitude is related to the magnetic-field-induced change of the viscosity.
The Correlation of 13C Chemical Shifts of Steroids with Atomic Charges Calculated by the Extended Hückel Molecular Orbital Method
Authors: Repmann Helmar
Published: February 2015

13C chemical shifts of several of the sterols and steroidal hormones which have been investigated by Reich et al. (J. Amer. Chem. Soc. 91, 7445 [1969]) are compared with the atomic charges derived from extended Hückel molecular orbital calculations for these molecules. The linear regression analysis of 126 observations for aliphatic carbons gives a correlation coefficient of 0.81, and a standard error of estimate of 8.2 ppm. The largest discrepancies arise for carbons in the neighbourhood of methyl groups, which cannot be attributed to deficiencies of the extended Hückel theory. The corrections for carbons in the α, β, and γ positions to a methyl group amount to + 11.75, - 6.44, and +4.45 ppm, respectively. The results are discussed in relation to the structural analysis of steroids.
Some Calculations Concerning the Pseudo-Kikuchi Pattern Contrast from Tilted Crystals
Authors: Pirouz P.
Published: February 2015

The theory of Hirsch und Humphreys1 has been applied to calculate the contrast across pseudo-kikuchi bands for tilted crystals. The crystallographic planes giving rise to the pattern are assumed to lie parallel to the undeflected electron beam. An asymmetry in contrast across individual bands is found, in agreement with experimental observations.

Intensity profiles and simulated patterns for several angles of tilt in the case of the undeflected beam perpendicular to the (111) reciprocal latice plane of a silicon crystal are presented.
Millimeter Wave Rotational Transitions of 16O12C32S and 16O13C32S
Authors: Larsen N. W. , Winnewisser B. P.
Published: February 2015

Rotational transitions of 16012C32S and 16013C32S in the ground vibrational state and of 16012C32S in several excited states have been accurately measured in the millimeter wave region for a minimum of four different J values. The analysis of the measured frequencies leads to rotational constants for the following vibrational states:

0 00 0 of 16O13C32S and

0 00 0, 0 1 1c 0, 0 1 1d 0, 0 20 0, 0 22c 0, 0 22d 0,

0 00 1 of 16O12C32S.

Since the two components of the 0 22 0 transitions were resolved, an analysis of the l-type resonance was carried out and the interval 0 22 0 - 0 20 0 has been determined to be -4.63(10) cm-1. The result is in good agreement with the presently available determination of this level from vibrational spectra.
Notizen: Bemerkungen zum Nachweis der Wellennatur von Ionenstrahlen / Remarks to the Demonstration of the Wave Nature of Ion Beams
Authors: Beier H.-J.
Published: February 2015

At sufficiently high energies (about 30 keV) the diffraction of ion beams at atoms can be observed. The steepness of the descending part of the interaction potential has a very sensible influence on the diffraction pattern. This is shown by comparison of the diffraction effect for different kinds of potentials.
On the Mathematical Definition of Entropy
Authors: Skagerstam Bo-Sture
Published: February 2015

We discuss the Baron-Jauch definition of entropy and show that it is the unique answer to an entropy which has the properties of extensivity, positivity and continuity in a weak sense. As an application we also show how one easily can derive the canonical distribution from this definition of entropy using information theoretical arguments.
Vergleich zwischen gemessenen und berechneten Emittanz-Diagrammen von Elektronenkanonen Reaktionskinetische Untersuchungen an neutronenbestrahlten Alkalihalogenid-Einkristallen / Comparison of Measured and Computed Emittance Diagrams of Electron Guns
Authors: Lauer Rolf
Published: February 2015

Emittance diagrams of electron guns were measured by means of a shadow method and compared with computed diagrams given in the literature. The calculated ray characteristics and particularly the paraxial ray data could be confirmed, but not the data for the spherical aberration constant. The experimental diagrams can be described by a fifth order parametric expansion of rayinclination and ray coordinate as a function of the ray inclination at the cathode. This expansion is compatible with an electron gun model consisting of two subsequent electrostatic lenses having third order aberrations only. A short survey on this article is given in 11.
Reaktionskinetische Untersuchungen an neutronenbestrahlten Alkalihalogenid-Einkristallen / Reaction Kinetic Investigations in Neutronirradiated Alkalihalide Single Crystals
Authors: Felix F. W. , Meier K. , Müller M.
Published: February 2015

It is often observed that the isothermal degassing of the systems KCl/Ar, CsBr/Xe, and CsJ/Xe cannot be described by Fick's law. According to the diffusion model of Hurst and Gaus one can interpretate such deviations by assuming a reaction of first order between rare gas atoms and lattice defects. This model explains qualitatively several experimentally observed phenomena very well.

A quantitative interpretation of the obtained results, however, leads to contradictions.
Eine Analyse der Methyltorsionsfeinstruktur von Rotationsspektren in angeregten Zuständen der S-S-Torsion beim Trideutero-methyl-methyldisulfid / An Analysis of Methyltorsion Finestructure in Rotational Spectra of Excited States of S-S-Torsion of Trideutero-methyl-methyldisulfide
Authors: Kuhler M. , Charpentier L. , Sutter D. , Dreizier H.
Published: February 2015

The microwave spectrum of CH3SS CD3 was investigated in the range of 5 -40 GHz. Rotational spectra in different states of the S-S-torsion were assigned. The methyl torsion fine structure of these spectra was measured and compared with calculations based on a Hamiltonian formulated for a model with two internal degrees of freedom, the methyl and S-S-torsion.
Graph Theory in Chemistry — Generalisation of Sachs' Formula
Authors: Mallion R. B. , Trinajstić N. , Schwenk A. J.
Published: February 2015

The Sachs' formula is generalised so that it can be applied to those (rooted) graphs which may be used to represent conjugated systems containing a restricted class of hetero-atoms.
Molecular g-Values and Magnetic Susceptibility Anisotropy Parameters of D2-Ketene. Sign of the Dipole Moment of Ketene
Authors: Sastry K. V. L. N. , Guarnieri A.
Published: February 2015

The rotational Zeeman-effect of D2CCO has been observed under high resolution. In addition to g-factors and susceptibility anisotropics the sign of the electric dipole moment has been determined after having remeasured the same parameters for normal ketene under identical conditions.
Mean Amplitudes of Vibration for Tetrahedral Molecules and Ions
Authors: Sharma D. K. , Pandey A. N. , Dublish A. K. , Rai S. N.
Published: February 2015

Mean amplitudes of vibration for 38 tetrahalides and 15 tetraoxides have been computed at temperatures T = 0° K , T = 298.15 °K and T=500°K employing most recent vibrational data. Müller's method has been followed in solving the two dimensional Cyvin's secular determinant. The results have been briefly discussed.
Über die doppelbrechende Phase der Mischkristalle von NH4Br mit TIBr. NH4Br mit CsBr und NH4Cl mit CsCl
Authors: Brauer Peter
Published: February 2015

The range of existence of the birefringent tetragonal phase of mixed crystals of NH4Br or NH4Cl and other isomorph halides with the same anion is being examined. Especially, it will be shown that by adding CsCl even NH4Cl can be caused to change into that phase, i. e. to behave qualitatively like NH4Br.
Temperature Dependence of the Work Function of Nickel
Authors: Christmann K. , Ertl G. , Schober O.
Published: February 2015

The variation of the work function of nickel with temperature was measured with clean (111) and (100) surfaces between 25 and 320 °C and up to 430 °C with Ni(110). In all cases the work function decreases linearly with temperature by 1.7 x 10-4 eV/°C. No anomaly (neither a jump nor a change of the slope dφ/dT) was found at the Curie point.
Energy of the Excess Electron State in Liquid Methane
Authors: Tauchert Wolfgang , Schmidt Werner F.
Published: February 2015

The energy of the electron conduction state in liquiud methane (T = 95 °K ) was measured to be V0 = 0.0 eV.
Kinetischer Adsorptions-Isotopie-Effekt von CH4 und CD4 bei Molekularströmungsversuchen / Kinetic Adsorption Isotope Effect of CH4 and CD4 in Molecular Flow Experiments
Authors: Roth W. , Gottwald B. A. , Haul R.
Published: February 2015

Transient molecular flow studies of CH4, CD4 and mixtures using a Pyrex glass capillary were carried out under UHV-conditions at temperatures between 77.4 and 115 K and pressures between 10-5 and 10-3 Torr (10-3<0<10-1). The simultaneous recording of different components of the gas mixtures is achieved by means of a quadrupole mass spectrometer. The temperature dependence of the observed adsorption isotope effects is discussed in terms of the changes of the internal and external vibrations of the molecules caused by adsorption. The behaviour of gas mixtures was simulated by a numerical calculation.
Monte-Carlo Simulation of a Classical Quadrupole Solid
Authors: Romano S.
Published: February 2015

The Monte-Carlo method is applied to a sample consisting of 256 linear point-quadrupoles, whose centers are fixed on a face-centered cubic lattice with the usual boundary conditions; the quadrupole interaction is characterized by an energy

. The electrostatic energy is evaluated by means of Ewald-Kornfeld’s method. Results are given for energy, specific heat and order parameters and compared with previous papers on the subject. A first-order phase transition is found at T=(1±1)Γ/kB.
Kontinuierliche Emission eines AlCl3-Lichtbogenplasmas / Continuous Emission of an AlCl3 Arc Plasma
Authors: Mück Günther
Published: February 2015

The emission spectrum of an AlCl3 arc plasma with core temperatures from 5600 to 6150 K is quantitatively measured in the wavelength region between 1800 and 8200 Å. In addition to the Al lines has been observed: The Cl affinity continuum, produced by the attachment of electrons to Cl atoms, the recombination continuum of the Al+ ions, the continuous bremsstrahlung of the electrons in the field of the Al+ ions, the continuous bremsstrahlung of the electrons in the field of the neutral Cl and Al atoms, and finally the association continuum of the AlCl+ molecular ions, produced by the attachment of Al+ ions to Cl atoms.
Kernresonanzuntersuchung der Molekülrotation in festem Benzol: T1-Spektroskopie / Nuclear Magnetic Resonance Investigation of Molecular Rotation in Solid Benzene: T1-spectroscopy
Authors: Wendt J. , Noack F.
Published: February 2015

We have extended Haeberlen’s and Maier’s NMR investigation of the molecular rotation in solid polycrystalline benzene (C6H6), performed in 1967 in the Larmor frequency range from 88 MHz to 22 MHz, to lower frequencies down to 4.4 MHz. In some cases monocrystalline samples were also studied. The extensive data show that the presently accepted model of purely uncorrected rotations of the benzene molecules around their sixfold axis has to be rejected. Instead, two results found, namely

- a slight increase of the rotational activation energy when approaching the melting point of benzene and

- the width of the T1 relaxation minima as a function of the reciprocal temperature suggest an additional relevance of correlated molecular motions, like e.g. the ‘gear-wheel mechanism’ first proposed by Cox. By appropriate modifications of Haeberlen’s theory, i.e. by assuming a rate equation with temperature dependent activation energy and by emphasizing the effect of simultaneous rotations of neighbouring rings compared with the purely statistical, uncorrelated case, we succeeded to describe the considered T1 measurements quantitatively.
Spektroskopische Diagnostik eines nichtthermischen He-Plasmas in der Hochstromfackel / Spectroscopical Diagnostics of a non-thermal He-Plasma Jet
Authors: Mauderer H. , Schmid G.
Published: February 2015

The properties of a low-pressure non-thermal He-plasma jet have been investigated. The gas temperature was obtained from the population densities of high excited He-levels. The electron density was determined both from the Stark-effect broadening of some He-lines and from the intensities of some forbidden transitions. The radial distribution of electron temperature was found by comparing the computed population densities of the He 31P level with the experimental values.
Neutron Total Cross-Sections at 18.8 eV
Authors: Dilg W.
Published: February 2015

Neutron transmission measurements were performed at 18.8 eV neutron energy on F, Al, Sc, V, Fe, Co, Cu, Zn and Nb, in order to acurately determine the "free" scattering cross-sections of these elements. Coherent neutron scattering amplitudes are derived for F, AI, Sc, Fe, Cu, Zn and Nb, using available experimental data of the isotopic and spin-incoherent cross-sections. Spin-dependent scattering amplitudes a(l+½) and a(l-½) are evaluated for the monoisotopes F, Al, Sc, V, Co and Nb.
ESR Studies on 205Tl Hyperfine Couplings in the Radical Cations of Tl(III)Porphyrins
Authors: Mengersen Chr. , Subramanian J. , Fuhrhop J.-H. , Smith K. M.
Published: February 2015

The isotropic 205Tl hyperfine couplings obtained from the ESR spectra of the radical cations of Tl (III) meso tetraphenyl porphyrin (TPP), octaethyl porphyrin (OEP) and octaethyl chlorin (OEC) are reported. The radical cations were generated by electrooxidation in dichloromethane as solvent. A Karplus-Fraenkel type bilinear relation is used to interpret the 205Tl couplings, taking into account the sigma-pi spin polarization of Tl -N bonds by the spin density at the nitrogen atoms in the ligand as well as the direct pi interaction of the orbitals of Tl with the pi orbitals of the ligand. It is shown that for the cation radicals of Tl porphyrins, both these mechanisms contribute to the Tl couplings whereas for the cation radicals of Co- and Zn-porphyrins the sigma-pi polarization alone is sufficient to account for the metal hyperfine couplings. It is suggested that Tl-hyperfine couplings can be used to estimate the nitrogen spin densities of porphyrin radical systems when the nitrogen splittings are not resolved in the ESR spectra.
Magnetische Konstanten der Molekeln CuF und GaF / Magnetic Constants of the CuF and GaF Molecule
Authors: Honerjäger R. , Tischer R.
Published: February 2015

The Zeeman effect in the microwave rotational spectrum of 63Cu19F and 69Ga19F has been measured in the ground vibrational state υ = 0 in order to determine the (gJ-factor and the molecular magnetic susceptibility anisotropy ξT :

63Cu19F: gJ = -0.0628(2) ; ξT/h = 540(60) Hz/(kG)2 ; 69Ga19F: gJ = -0,06012(12) ; ξT/h = 521 (17) Hz/(kG)2. The molecular quadrupole moment and its electronic part are derived from the values of gJ,ξT and the rotational constant B0 . - The hyperfine structure of the Zeeman lines enabled a more or less rough determination of the magnetic shielding anisotropy of the nuclei 63Cu and 69Ga respectively:

σT(63Cu) = -1760(830) · 10-6 ,

σT (69Ga) = - 386(165)·10-6.
Light Diffractograms of Electron Micrographs at Tilted Illumination
Authors: Hoppe W. , Köstler D. , Sieber P.
Published: February 2015

Light diffractograms of electron micrographs at tilted illumination have proved the compensation of chromatic aberration and the enhancement in resolution predicted by the theory.
Resonanzstreuungsparameter für atomaren oder molekularen Wasserstoff in einem simultan mit Vakuum-UV und sichtbarem Lieht bestrahlten Plasma / Resonant Scattering Parameters for Atomic or Molecular Hydrogen in Plasmas Simultaneously Irradiated with Vacuum UV and Visible Light
Authors: Norton B. A.
Published: February 2015

Simultaneous resonant scattering of Lyman and Balmer radiation in low-density (Ne≲ 1014 cm-3) Hydrogen plasmas has been examined. The equations governing the rates of population of the first few excited levels are solved in the case of intense pumping. Parameters are obtained which relate the total atomic or molecular density to the population density in the third level and thus also to the intensity of the first Balmer line which is easy to measure experimentally. A possible means of obtaining sufficient UV power for this method is also discussed.
Population Densities and Ionization Coefficients of Fast Transient Hydrogen Plasmas
Authors: Cacciatore M. , Capitelli M.
Published: February 2015

Population densities and ionization coefficients of transient hydrogen plasmas have been calculated for typical ionization and recombination conditions. The results have been obtained by solving a system of differential equations by means of the Runge-Kutta method. Each equation describes the temporal evolution of a quantum state belonging to the plasma. Two initial conditions have been studied: i) The number density populations of the excited states are in Saha equilibrium with the electrons ii) the densities of excited states are equal to zero, whereas the initial condition for the ground state density is caracterized by a non-equilibrium parameter b1(t = 0) =n1/n1E > which has been varied from 106 to 10-2. Typical results for electron number densities ne ranging from 108 to 2.5 · 1013 p/cm3 and electron temperatures ranging from T = 8000 to 16000 °K are presented and discussed.
Internal Cation Mobilities in the Molten Systems LiNO3-TlNO3 and RbNO3-TlNO3
Authors: Kawamura Kazutaka , Okada Isao , Odawara Osamu
Published: February 2015

The relative differences in internal cation mobilities are measured for the molten systems LiNO3-TlNO3 and RbNO3-TlNO3 over a wide range of temperature and concentration by means of counter-current electromigration technique (Klemm's method), and the internal mobilities are calculated from the existing data on the electric conductivity for these systems. For the system LiNO3-TlNO3 , a marked dependence of the relative internal mobility differences on temperature is found particularly in the Li+ rich region, and a considerable concentration dependence is found over the investigated temperature range. This is qualitatively explained in terms of a model which takes into account mainly the differences of the cation-anion pair potentials and of the sizes of the two cations. On the other hand, for the system RbNO3-TlNO3, only a slight temperature dependence is observed and no concentration dependence, if present, is detected within the experimental accuracy.
Isotope Effect of Cation Electromigration in Molten Lithium Chloride-Nitrate-Mixtures
Authors: Ljubimov Vladislav , Lundén Arnold
Published: February 2015

Molten mixtures of lithium chloride and nitrate, including the decomposition products nitrite and oxide, were electrolysed at about 600 °C with gaseous electrodes. The relative mobilities of the lithium isotopes were studied. The mass effect (relative difference in mobility divided by relative difference in mass) is 0.063 for a mixture with 20% Cl- and 0.069 for 80% CI-, which both are more than 30% smaller than those interpolated from the isotope effects of pure LiNO3 and LiCl. It is concluded that the lithium ions interact more strongly (with the anions and/or with each other) in a melt containing several anions than in a pure melt. The experiments also yield some information about the mobilities of the anions present in the melt.
The Density at 25 °C of D2O with Natural Oxygen Isotopic Composition
Authors: Babeliowsky T. , Brulmans J.
Published: February 2015

In measuring the influence of oxygen isotopic composition and of hydrogen content on the density of heavy water an extrapolation was made to 100% D2O with natural oxygen isotopic composition, starting with the density of a highly enriched heavy water (99.95% D2O, about natural oxygen isotopic composition).

A value of 1104.481 kg/m 3 at 25 °C was obtained.
Thermal Expansion of Heavy Water between 7 and 26 °C
Authors: Brulmans J. , Verdonck J. , Eschbach H. L.
Published: February 2015

Using six carefully calibrated quartz floats the thermal expansion of water with a D2O content of 99.74 mole % has been measured between 7 and 26 °C. The extrapolation to 100% D2O with natural oxygen isotopic composition is made.
Waldmann-Snider Collision Integrals and Nonspherical Molecular Interaction
Authors: Köhler W. E.
Published: February 2015

The binary scattering amplitude matrix is derived from the general interaction potential between linear molecules. The first order distorted wave Born approximation (DWBA) is used which is applicable for small nonsphericity of the interaction. The molecular cross sections determining the most important Waldmann-Snider collision integrals are calculated. In particular, the scattering cross section, the orientation cross sections for vector-and tensor polarization and the reorientation cross sections for the tensor polarization of the rotational angular momenta are treated. For a simple interaction model for HD (HT) molecules the DWBA-scattering amplitude is evaluated analytically. The relaxation cross section of the tensor polarization, σT , and the coupling cross section of friction pressure tensor and tensor polarization, ση,T, are calculated for room temperature and compared with experimental values.
Gamma-Ray Induced Luminescence of Silica Gel
Authors: Kirmaier P. , Rabe J. G.
Published: February 2015

The thermoluminescence glow curve of γ-irradiated silica gel investigated between 77 °K and 600 °K is a broad band extending from 80 °K to ~ 400 °к. The emission occurs at ~ 450 nm. Shallow traps (0.1 - 0.2 eV) are responsible for most of the light emitted. The distribution of trap depth and the increase of trap density toward the band edge is tentatively attributed to the dis-ordered structure of silica gel in accordance with previous suggestions concerning glasses. In contrast to the growth with radiation dose of color-and paramagnetic center concentration, luminescence is already saturated at about 1 Mrad. The luminescence decay follows the hyperbolic relation derived by Adirowich for a bimolecular process in the case of retrapping for which evidence is presented. At very low radiation doses the initial intensity of luminescence was proportional to the square of the dose rate as expected for a bimolecular reaction.

Removal of surface OH groups as accomplished by raising the degassing temperature of the gel results in an increase of luminescence intensity by several orders of magnitude. Hydrogen and oxygen when adsorbed prior to or subsequent to irradiation reduce the luminescence intensity to about one per cent of that observed in vacuum or in the presence of helium. The results are dis-cussed in terms of surface reactions involving free and trapped charge carriers generated during irradiation.
Ein Beitrag zur Radiofrequenz-Mikrowellen-Doppelresonanz-Methode / A Contribution to the Radiofrequency Microwave Double Resonance Method
Authors: Schwarz R. , Dreizier H. , Guarnieri A.
Published: February 2015

Experiments are reported which extend the useful Radiofrequency Microwave Double Resonance Method to higher Radiofrequencies. A special absorption cell was constructed for this purpose.
Third Virial Coefficients for Ar, Kr, and Xe Including Nonadditive Effects
Authors: Caligaris R. E. , Scalise O. H. , Grigera J. R.
Published: February 2015

In this work we adopt the RMMV potential function proposed by Davis and calculate third virial coefficients for Ar, Kr, and Xe. Nonadditive effects due to dipole-dipole-dipole and dipole-dipole-quadrupole terms are included. We found good agreement between theoretical and experi-mental values for Ar and Kr, but not for Xe.
Die Molekülstruktur des Vanadium-(N-chlorimid)-trichlorids, Cl3V=NCl, und des Vanadiumoxidtrichlorids, Cl3V = O, in der Gasphase / The Gas Phase Molecular Structure of Vanadium(N-Chlorimide)Trichloride, Cl3V=NCl, and Vanadium Oxide Trichloride, Cl3V=O
Authors: Oberhammer H. , Strähle J.
Published: February 2015

The molecular structures of Cl3V = NCl and Cl3V = O were determined by gas-phase electron diffraction. For both molecules the rα
0-structure was converted to restructure. In the case of Cl3V=O the necessary corrections were taken from the literature while for Cl3V=NCl an approximate force field was evaluated from the infrared spectra of the solid compound for calculating these corrections. The following rα0 parameters were derived for Cl3V = NCl: V = N = 1,651 (6), N-Cl = 1,597 (8), V - Cl = 2,138 (2), ⦓ ClVCl = 113,4° (0,3) and ⦓ VNCl = 169,7° (4,2). The most interesting result of this investigation is the structure of the V = N -Cl group which is almost linear and has a very short N -CI bond distance. Concerning the VNCl group the gas-phase results agree very well with the crystal structure. For vanadyl chloride the following rα0-values were obtained: V = 0 = 1,571 (4), V - Cl = 2,137 (1) and ⦓ ClVCl = 111,0° (0,1°). The error limits given in thousandth parts of an Angstrom or degrees are the threefold standard deviations of the least squares analysis.
Mass Spectra and Ion Chemistry of Methylphosphine, Dimethylphosphine and Dimethyldeuterophosphine, Investigated by Ion Cyclotron Resonance Spectrometry
Authors: Wanczek Karl-Peter
Published: February 2015

The mass spectra and the ion molecule reactions of methylphosphine, dimethylphosphine and dimethyldeuterophosphine have been studied by ion cyclotron resonance spectrometry. About 50 ion molecule reaction are observed for each compound. The product ions can be classified as ions with two phosphorus atoms: P2R5
+, P2R3
+, P2R2
+ and P2R+ (R = CH3 or H), as phosphonium and phosphinium ions and ions resulting from collision dissociations and charge exchange reactions. Tertiary ions with three phosphorus atoms like CH3P3H2
+ (from CH3PH2) and (CH3)4P3H2 (from (CH3)2PH) have also been detected. The mechanisms of the ion molecule reactions, rearrangements, P -H- and C-H-reactivities and product ion structures are discussed, using in the case of dimethylphosphine the results obtained with the deuterated compound. Rate constants of formation of the more abundant product ions from the molecular ion and the CH3P+ ion, both odd electron particles, have been determined. The reactions with dimethylphosphine have much smaller rate constants than the reactions with methylphosphine.
Über den Zusammenhang von Rauschen und Schichtungen der positiven Säule beim kataphoretischen He-Cd-Laser / Correlation of Noise and of Striations in the positive Column of the cataphoretic He-Cd-Laser
Authors: Fromm D. , Schmidt E.
Published: February 2015

The noise of the laser signal of the cataphoretic He-Cd-Laser (441,6 nm) and the spontaneous emission are investigated spectroscopically in end on and side on observation as function of Cd and He atom density. Commencing with Cd atom densities of 5 · 1014 cm-3 witish and blue striations of the positive column develop, that are directly connected with a sinoidal modulation of the voltage and the Cd, Cd+, and He emission. Electron temperature and Cd+ density are higher in the whitish zones than in the blue zones. The noise is attributed to plasma disturbations, for example Cd density fluctuations. The striations are explained on the basis of Wojaczek's theory of electron temperature waves.
Thermoelectric Power of the Molten Systems (Cu, Me)Cl and (Cu,Me)Br (Me = Na, K, Rb, Cs)
Authors: Pezzati Elisabetta , Magistris Aldo , Schiraldi Alberto
Published: February 2015

The initial thermoelectric power of the molten systems (Cu, Me) Cl and (Cu,Me)Br (Me=Na, K, Rb, Cs) was determined using copper electrodes. The results are compared with previous results obtained from the systems (Cu, Me) I and (Ag, Me)X (X = Cl, Br, I).
Leitfähigkeit des flüssigen Systems Ameisensäure + Essigsäure / Conductivity of the Liquid System Formic Acid + Acetic Acid
Authors: Haase R. , Giraldo H. Jaramillo- , Dücker K.-H.
Published: February 2015

Results of measurements of the electric conductivity and of the molar volume for the water-free liquid system formic acid-f-acetic acid are presented. They cover the whole composition range at temperatures between 0 °C and 50 °C. The equivalent conductivity and the activation energy are also given.
Adiabatische Invarianz im Mittel / Adiabatic Invariance in the Average
Authors: Janicke L.
Published: February 2015

We study the possibility to construct an adiabatic invariant for charged particles in electromagnetic fields, that vary strongly in space but only slowly in time (measured by a small parameter ε). We specialize to those fields, where the motion of the particle is described by a Hamiltonian that corresponds to a one-dimensional oscillator with a potential exhibiting two minima. This type of potential can occur in the case of one-dimensional fields with neutral sheets. The action integral I=∮ p dq is no longer an adiabatic invariant for particles with an energy near the value of the inner maximum of the potential, nor is it a continuous function of the energy. The second difficulty can be removed by proper redefinition. Then by using the area conservation in the phase plane it can be shown that for any arbitrary particle ensemble in the phase plane of the one-dimensional oscillator the mean value of the action integral is adiabaticly invariant to order ε ln4 ε. Under certain circumstances it can happen that a coherent ensemble splits up into two separated groups. It will be shown that this also can be understood essentially as an adiabatic process.
Test of the Unitary Pole Approximation to the Malfliet-Tjon Potential for Elastic Neutron-Deuteron Scattering
Authors: Ziegelmann H.
Published: February 2015

The quality of the unitary pole approximation to the soft-core Malfliet-Tjon potential is demon-strated for elastic neutron-deuteron scattering above breakup threshold.
The Influence of Deviations from the Maxwellian Electron Distribution on the Population densities in a low Temperature Monatomic Plasma
Authors: Claaßen H. A.
Published: February 2015

A selfconsistent solution with respect to both free and bound electron energy states is presented for a low temperature monatomic plasma. The deviations from a Maxwellian electron distribution under the action of unbalanced resonance transitions of the plasma atoms are incorporated in analytical form using a recursion formula, which links the high energy tail of the electron distribution function to its low energy part. The unbalance of the resonance level may be due to diffusion processes and/or radiation escape, which reflect the influence of the plasma boundaries. The population densities of the bound electron energy states are numerically determined by an iteration procedure. The calculations were performed for a cesium plasma both without and with consideration of resonance level diffusion and ambipolar diffusion. As is to be expected, the effect of a disturbance of the electron distribution on the population densities increases with decreasing electron density and increasing electron temperature.
Zur allgemeincn Formulierung der Fliefibedingung unter Beriicjisichtigung der Anisotropie und des Bauschinger-Effektes / On the general Formulation of Yield Conditions under Consideration of Anisotropy and Bauschinger-Effect
Authors: Troost A. , Betten J.
Published: February 2015

In this paper, some aspects of the isotropic and anisotropic yield conditions are discussed on the base of the plastic potential by introduction of partial potentials. The significance of the Bauschinger-Effect is investigated, in order to describe the mechanical behavior of materials in which the magnitude of the uniaxial yield strength depends on the sign of stress. This generalized concept is successfully applied to titanium sheets. The theory is compared with experimental results.
Preparation and Superconducting Properties of Niobium Carbonitride Wires
Authors: Bernhardt K.-H.
Published: February 2015

Superconducting niobium carbonitride wires Nb(CyNx) has been prepared by a diffusion process in two steps, first diffusing carbon from methane into niobium wires and then nitrogen into these carbonized samples. The optimum conditions for these preparations have been investigated in detail. All samples have been analysed quantitatively for C, N and Nb. The carbonizing as well as the following nitriding of the wires has been investigated under various conditions. The maximum of the transition temperature of the Nb(CyNx) wires prepared by this two steps diffusion process is reached for the same composition y, x as for sintered samples. But the value is about 0.4 K lower.
Analysis of the Relaxation of Wall Electrons in a Plasma
Authors: Ecker G. , Riemann K.-U. , Scholz A.
Published: February 2015

A procedure is developed which renders the simultaneous description of angular and energy relaxation of wall electrons in a plasma possible. The plasma is assumed to be field free, allowance is made for elastic and inelastic collisions with neutrals, as well as for electron-electron encounters. The procedure is based on an expansion in terms of the eigenfunctions of a suitable part of the kinetic equation. In the zeroth order, the problem is reduced to a boundary value problem of the Sturm type, and subsequent solution of a singular integral equation by standard technique. To account for the rest of the kinetic equation, we construct a Green′s function which forms the basis for an iteration process. The application of the procedure is illustrated with an example.
Messung der Krypton-85-Aktivität der atmosphärischen Luft / A Method for Measurement of the Krypton-85-content in the Atmosphere
Authors: Stockburger H. , Sittkus A.
Published: February 2015

To measure the Kr-85 content in the atmosphere we developed a simple method. Within a time internal of five to ten days (depending on the moisture of the air) five to ten m 3 of air (NTP) are pumped through activated carbon (pressure 300 torr, temperature 77 °K). When sampling time is over, the carbon is heated to 470 °K. This gives a gas sample of 4 1 with more than 90% of the atmospherical krypton in 3 hours. With a further step of enrichment, the volume of the sample is reduced to 100 ml. The final separation of krypton from O2 , N2 , CO, CO2 and Xe is made by gaschromatography at room temperature with methane as eluent gas (duration 25 min). The Kr-fraction is transported to a proportional counter (200 ml). The overall yield is 90%. The overall error of the Kr-85 content is near 1%. Data are given for the time of 15. 6. 1973 to 29. 12. 1974.
Kosmogener Überschuß von 40K und Fluß schneller Neutronen in Meteoriten / Cosmogenic Excess of 40K and the Flux of Fast Neutrons in Meteorites
Authors: Stegmann W. , Begemann F.
Published: February 2015

Results are reported of a mass spectrometric investigation of the content and isotopic com-position of potassium from the mesosiderite Emery (silicate phase) and the chondrite Elenovka (bulk). Normalized to the Nier value of 39 K/ 41 K=13.47 the 40 K in Emery (K-content 220 + 25 ppm) was found to be enriched by (4.03 ± .30)%, the potassium from Elenovka (760 ± 50 ppm) to be indistinguishable from terrestrial potassium. - Evidence is presented that the excess 40 K in the silicates from Emery (Ca-content 6.06 weight %) has been produced essentially by secondary cosmic ray neutrons via the 40 Ca (n,p) -reaction. The total excess of (2.57 ± .39) x 1014
40 K-atoms/g Ca together with the excitation function of the 40 Ca (n,p) -reaction and the neutron flux spectrum of Arnold, Honda and Lal yields a dose of fast neutrons (2 MeV ≦ En ≦ 100 MeV) Φ · T = (7.2 ± 1.1) x 1016 neutrons /cm2 and an average flux during the cosmic ray exposure age T = (134 ± 12) Myrs of Φ = (17.4 ± 3.1) neutrons /cm2 sec. - A comparison of the neutron induced production rate of 40 K from Ca with that of 21 Ne from Mg and 38 Ar from Ca indicates the Arnold, Honda, Lal flux spectrum to be adequate for En ≲ 20 MeV but that it underestimates the number of neutrons with higher energies.
Mögliche Deutungen quadratischer Fließbedingungen bei Isotropie und Anisotropie / Physical Interpretations of Isotropic and Anisotropic Yield-Conditions
Authors: Troost A. , Betten J.
Published: February 2015

The paper introduces shear stress quantities, which are the difference of two stress tensors, the actual one and one produced by rotating the axes. This quantities have physical significance. In the vectorial representation in the principal stress space and the principal shear stress space the paper give some interesting relations. The authors observe that Hill′s anisotropic yield criterion can be derived from their shear stress quantities by introducing a measure tensor and gave a physical explanation to Hill′s condition.
An ab initio Calculation of the Force Constants, Vibrational Frequencies, and Equilibrium Geometry of HCP
Authors: Botschwina P. , Pecul K. , Preuss H.
Published: February 2015

All the harmonic, the diagonal cubic and quartic stretching and the semidiagonal cubic force constants of HCP have been calculated from Hartree-Fock wavefunctions by the force method of Pulay. The force constants are in good agreement with the experimental ones, except for FRR, Faa, FRr, FRaa, and Fraa the latter two being rather uncertain from experiment. From the harmonic force constants, harmonic frequencies have been calculated by the method of Wilson and Eliashevich. The equilibrium geometry of HCP has been calculated by the force relaxation method of Pulay.
A Study of the Cubic Phase of Solid Acetylene-d2
Authors: Koski Harri K.
Published: February 2015

The powder pattern of crystalline cubic deuterated acetylene recorded by thermal neutron diffraction technique and the Pa3 crystal structure assigned to the high phase of C2H2 are com-pared. The observations are not in disagreement with the theoretical pattern. Values for the lattice parameters in a narrow temperature range are given.
Irradiation Damage Centers in Magnesiumhypophosphite
Authors: Köksal F. , Yüksel H.
Published: February 2015

An analysis of the electron spin resonance spectra of gamma-irradiated crystals of magnesium-hypophosphite, Mg (H2PO2)2 · 6 H2O, has shown that the main long-lived paramagnetic species produced by gamma-irradiation are HPO2
- and PO3
- ionic radicals. The hyperfine interaction tensor of the phosphorous nucleus has the principal values T|| = 1674, T⊥ = 1221 Mc/s in HPO2
- and T|| = 2490, T⊥ = 1847 Mc/s in PO3
-. In HPO2
- , interaction of the unpaired electron with the proton gives rise to an almost isotropic hyperfine coupling of 233 Mc/s. These results indicate that the orbitals occupied by the unpaired electron in both HPO2
- and PO3
= are sp3 -hybrid σ-orbitals centered on the phosphorous nuclei.