bluuebunny/crossref_metadata_2025 huggingface dataset:
Absolutmessung der kontinuierlichen Strahlung des Heliums im Lichtbogen von λ = 109 bis 540 nm / Measurement of the Helium Continuum Radiation from λ = 109 to 540 nm in an Arc Plasma
Authors: Thoma P.
Published: February 2015

Absolute helium emission coefficients have been measured from 540 nm down to 109 nm in the near vuv. The radiation originates from the axis of a cylindrical He-arc of 2 mm ∅ at one atmosphere with electron temperatures between 25000 K and 26500 K. The electron densities range from 3.0 · 1016 cm-3 to 4.0 · 1016 cm-3 and have been determined independently from other plasma parameters by means of line shape measurements. The density of atoms and their kinetic temperature have been calculated from the energy balance of the electrons and Dalton's law. Comparison of the measured helium continuum emission coefficients with theoretical calculations in the wavelength range from 540 nm to 400 nm shows that, in this experiment, the radiation due to bremsstrahlung in the field of atoms must not be neglected. Taking into account this contribution very good agreement with theoretical calculations over the whole investigated spectral range from 540 nm down to 109 nm has been found. Thus the present experiment confirms the theoretical results for the photoionisation coefficients from the n = 2 and n = 3 levels. On the basis of these results the helium continuum radiation may be used for calibration purposes, which is of particular interest in the vuv.
Calculation of the Lifetimes of Localized Electronic Vacancies in Cyclic Molecules
Authors: Spehr R.
Published: February 2015

For a benzenelike ring of six carbon atoms the dissipation of localized electron vacancies of π and of σ symmetry is calculated. The vacancies are described by Wannier sums. The calculation yields lifetimes of localization of about 10- 16 s in both cases. These values are shorter by two orders of magnitude than any period of molecular vibrations. Therefore such transiently localized vacancies, which can be caused by irradiation or by statistical fluctuations, will not destroy any bond in organic molecules.
On the Theory of Thermally Weighted Electron-Phonon Transition Probabilities
Authors: Schupfner J.
Published: February 2015

We present a refined calculation method for the phonon part (Franck-Condon Overlaps) of the transition probabilities of electron-phonon radiative and non-radiative transitions in crystals. The evaluation of the thermal averaged Franck-Condon integrals is a purely algebraic method and the transition probabilities we use are derived from first principles and completely atomistic. For the electronic transitions we take into account the frequency shift of the lattice and the change of the phonon normal coordinates. Explicit formulae of the phonon parts are derived and it is shown that the common transition probabilities used in literature are special cases of our functional calculation technique.
Part 1: X-Ray High-Angle Scattering and Ultrasonic-Measurements
Authors: Hermann Gerhard , Bek Richard , Steeb Siegfried
Published: February 2015

By means of X-ray scattering and ultrasonic experiments, the structure of different melts of the Cd-Ga system was investigated. The structure factors S (q) obtained for the pure elements agree well with those reported by other authors. The concentration dependence of the structure factors shows no special features. From the structure factors, the total pair-distribution functions were calculated by a Fourier transformation. The nearest-neighbour distances, obtained from the total pair-distribution functions, amount to 3.04 Å for pure Cd and 2.83 Å for pure Ga and are nearly constant for all alloys. The concentration dependence of the experimental nearest-neigh-bour distances and coordination numbers was determined and is compared with statistical distribution and macroscopic segregation models. These comparisons tend to indicate a preference for like-atom neighbours. From the long-wavelength limit S(0) of the structure factors of Cd and Ga, the isothermal compressibilities were calculated. These show a satisfactory agreement with those calculated from adiabatic sound velocity data. The anomalous ultrasonic absorption of a single melt with nearly critical concentration indicates the existence of concentration fluctuations. This result is in agreement with those obtained by X-ray smallangle scattering experiments which are described in Part 2 of this work [1].
Structure of Cd-Ga Melts Part 2: X-Ray Small-Angle Scattering
Authors: Hermann Gerhard , Rainer-Harbach Georg , Steeb Siegfried
Published: February 2015

X-ray small-angle scattering experiments were performed on nine melts of the Cd-Ga system at different temperatures up to 440°C. Evaluation of the data follows the Ornstein-Zernike theory of critical scattering, thus yielding correlation lengths ξ of concentration fluctuations and the long-wavelength limit Sec (0) of the Bhatia-Thornton structure factor. Studies of the concentration and temperature dependence of ξ and SCC (0) indicate that the critical point occurs at cc = 50.0 ± 1-0 at % Ga and Tc - 295.2 ± 0-1° C. For a melt with the critical concentration, SCC (0) increases up to 3500 times the ideal S1d
CC (0)=C
A
C
B-This indicates a strong segregation tendency. In the vicinity of the critical point of the Cd-Ga system, experimental correlation lengths ξ > 100 A were obtained. The critical-point exponents ν and γ were determined. It follows that the behaviour of a critical Cd-Ga melt satisfies the prediction of the classical mean-field theory for higher temperatures, whereas, within experimental accuracy, the lattice-gas predictions are satisfied upon approaching the critical temperature.
A Note on Poincaré's Principle and the Behaviour of Moving Bodies and Clocks
Authors: Sjödin Torgny
Published: February 2015

Exploiting the wave properties of light, the isotropy of space, and the homogeneity of space and time, the functions describing the behaviour of moving bodies and clocks are derived from Poincare's principle about the impossibility to detect absolute motion.
Hartree-Fock Calculations of the Interaction Potential Parameters for Noble-Gas Atoms
Authors: Bielski A. , Wasilewski J.
Published: February 2015

The interaction potential parameters (〈rk〉, Hindmarsh’s radius rH, C6, C8, C12) are calculated for the ground and some excited configurations of the noble-gas atoms from the Hartree-Fock functions. A formula for the C8 constant is derived.
Characteristic Normal Modes of Vibration and Generalized Normal Forces: Basic Properties and Relation to Fundamental Molecular Constants
Authors: Alix A. J. P. , Rytter E.
Published: February 2015

A survey is given of the simplified formulae for energy distributions, force constants, secular equations, Coriolis coupling constants, isotopic substitutions, compliances, mean amplitudes, bond moment and polarizability parameters, interaction coordinates and restoring forces in the cases where either a completely characteristic normal mode or a generalized normal force can be assumed. The obtained results may be of use for the following main purposes: (i) computation of quantities which can be employed in the assignment of spectra, band shapes, intensities ... (ii) evaluation of fundamental molecular constants and isotopic shifts which can be approximated with good accuracy. As illustration, the equations have been applied sucessfully to two-dimensional cases and to Molybdenum-hexacarbonyl.
Resonance Absorption of a Wavelength-shifted Probe Beam in a Laser-Produced Plasma
Authors: Maaswinkel A. G. M.
Published: February 2015

The resonance absorption of a weak probe beam in a plasma, produced by 0.53 μm laser irradiation of planar targets at 1014 W/cm2, has been investigated. The probe beam (λ= 1.06 μm) could be delayed in time relative to the 0.53 μm pulse. Thus a shift of the resonance absorption maximum towards smaller angles of incidence for increasing time delays was found. This is expected on account of the hydrodynamic expansion.
The Application of the Memory-Function Formalism to Dielectric Relaxation
Authors: Bordewijk P.
Published: February 2015

The application of the memory-function formalism to dielectric relaxation is reconsidered. It is shown that the so-called Corresponding Micro-Macro Correlation theorem is not valid and that for a single macroscopic dielectric relaxation time, the single-molecule dipole correlation function may nevertheless be non-exponential. The deviations from the exponential decay for the single-molecule dipole correlation function are due to spatially dependent orientational correlations, and can at least partly be interpreted in terms of dielectric friction. The unsureness about these correlations implies that it is simpler to determine the rotational diffusion coefficient from the collective orientation correlation time as determined from dielectric measurements than from the single-molecule dipole correlation function as obtained from infrared spectroscopy.
Condensed Aromatics. Part VII
Authors: Neerland Grethe , Cyvin Bjørg N. , Brunvoll Jon , Cyvin Sven J. , Klaeboe Peter
Published: February 2015

A simple, five-parameter force field approximation for the out-of-plane vibrations of aromatic molecules is applied to anthracene and pyrene. The calculated frequencies are remarkably well compatible with previous calculations and observed data. Among the given experimental frequencies are new data recorded in infrared for anthracene and both in Raman and infrared for pyrene.
The Molecular Structure of (Dichloromethyl)-trichlorosilane
Authors: Typke V. , Dakkouri M. , Schiele M.
Published: February 2015

The molecular structure of (dichloromethyl)-trichlorosilane has been determined by gas phase electron diffraction. It has been found that the effective structure of the molecule has C1-symmetry with an angle of rotation τ and a tilt angle ψ of the SiCl3-group. Several vibrational amplitudes were fixed at values calculated from transferred Urey-Bradly force constants.

Systematic errors resulting from the uncertainties of the fixed parameters have been calculated applying the rules of error propagation. The most important structural parameters (rg in Å, angles in degrees) are: r(Si-C) = 1.905(10), r(Si-Cl) = 2.019(1), r(C-Cl) = 1.774(4), r(C-H) = 1.16(4), ∢ (C-Si-Cl) = 109.8(3), ∢(Si-C-Cl) = 111.4(8), ψ= 4.1(1.0), τ= 6.7(1.4) (the errors in parenthesis include the systematic contributions).

Comparison is made with structural data of other representatives of the series CH3-mClmSiCl3 (m = 0, 1, 2, 3).
Notizen: The Inhibitor Agent in Subramanian's Dislocation Etchant for KCl
Authors: Rodriguez F. , Moreno M.
Published: February 2015

An optical absorption study of Subramanian's solution shows that a [FeCl4]- complex is formed. This complex is mainly responsible for the possibility of observing dislocations in KCl using this solution as etchant.
Notizen: Analysis of Higher Electronic States of Azulene and Its Halogenoderivatives in n-Pentane and n-Hexane Matrices at 77 K from Absorption Spectra
Authors: Bałuk P. , Kawski A. , Kałas M. , Jaśkiewicz S.
Published: February 2015

Highly resolved vibrational structures of the S2← So electronic transition and the 0-0 S3 ← So and S4 ← So transitions of azulene, 2-chloro-azulene, 1,3-dichloro-azulene, 1,3-dibromo-azulene and 1,3-diiodo-azulene in n-pentane and n-hexane at 77 K have been obtained and discussed.
The Viscosity Coefficients of Biaxial-Nematic Liquid Crystals. Phenomenology and Affine Transformation Model
Authors: Baalss Dieter
Published: February 2015

The viscosity tensor of biaxial-nematic liquid crystals contains 16 independent elements. A complete set of these viscosity coefficients is introduced and related to experimentally accessible quantities. Furthermore, the flow alignment and its stability against an arbitrary infinitesimal disturbance are discussed. By the affine transformation model, formerly established for the uniaxial symmetric case, one can express the viscous anisotropy of perfectly ordered biaxial ellipsoids in terms of the two viscosities of an isotropic reference system and the axes ratios of the nonspherical particles.
Molecular Ordering in Nematic MBCA and EPAPU
Authors: Sreehari Sastry S. , Venkata Rao V. , Narayana Murty P. , Satyanandam G. , Sundar Raj T. F.
Published: February 2015

By EPR, two nematic liquid crystals (MBCA and EPAPU) were investigated using a steroidal nitroxide spin probe. In both liquid crystals the isotropic-nematic phase transition is of first order. The observed variation of the order parameter with temperature is compared with predictions from the Maier-Saupe and Humphries-James-Luckhurst models and with results obtained by several other experimental techniques.
A Deuterium NMR Study of some Ammonium Tetraphenylborates
Authors: Gruwel Marco L. H. , Wasylishen Roderick E.
Published: February 2015

Deuterium nmr has been used to study the rotational dynamics of the ammonium ion in ammonium tetraphenylborate and of the cation in a series of methylammonium tetraphenylborates. The results of variable temperature 2H relaxation measurements (T1Z and T1Q) on the parent compound, ND4B(C6H5 )4 , lead to a low activation energy for reorientation of the ND4+ ion, 5.0 ± 0.5 kJ mol-1 , indicative of weak cation-anion interactions. Related studies of the tetramethyl-d12 ammonium salt indicate rapid jumps of the whole cation (τ ≪ 10-5S) over the complete temperature range investigated, 137 to 385 K, with an activation energy of 14.1 + 0.5 kJ mol-1 . Deuterium nmr lineshape studies of the methylammonium salt indicate rapid reorientation of the CD3 and ND3 groups about their C3 axes; however, the motion of the C - N axis is restricted to large amplitude librations. Similar studies of the dimethylammonium salt indicate methyl group jumps at 245 K; at temperatures above 320 K the cation also undergoes two-site jumps about the C2 axis. In the case of the trimethylammonium salt, the nmr lineshapes indicate methyl group jumps superimposed on C3 rotations of the complete cation about the N - H bond axis over the temperature interval 185-348 K. In all the tetraphenylborate salts studied, the 2H nmr lineshapes indicate substantial librational motion of the cation at room temperature.
Luminescent Centres of Td Symmetry in "Cold" Activated ZnS-Mn
Authors: Kynev K. , Maneva N. , Angelov S.
Published: February 2015

By coprecipitation of ZnS and MnS in excess of Na2S, luminescent centres are built differing considerably from those in zinc salt excess. ESR data give evidence of centres of Td symmetry.
Energy Gap and Line Shifts for H-Like Ions in Dense Plasmas
Authors: Kilimann K. , Ebeling W.
Published: February 2015

Based on the results of a foregoing paper (Z. Naturforsch. 44 a, 519 - 523 (1989)) the density-dependence of the discrete energy states and the continuum level is calculated with better accuracy. A static approximation to the line shifts is derived and discussed
Influence of Temperature on the Removal Rates of CH2(ã1A1 ) by Inert Gases and Hydrocarbons
Authors: Wagener R.
Published: February 2015

The reactions of CH2(ã1A1) with the inert gases He, Ar, N2 , with H2 and with the hydrocarbon reactants CH4 , C2H6 , C2H4 and C6H6 have been investigated at 210, 295 and 475 K. CH2(ã1A1) was generated by pulsed laser photolysis in a quasistatic thermostated gas cell and detected by pulsed laser induced fluorescence. Concentration profiles of CH2(ã1A1) were recorded under first order reaction conditions by varying the time delay between the photolysis and the probe laser pulses. The second order rate constants determined at room temperature are in good agreement with those of earlier work. No differences between the removal rates of ortho-and para-methylene nuclear spin states by the inert gases were observed. The experimental rate constants were fitted to an expression k = A -(77295 K)n. The results are given in the form {A ± AΔA} {n ± Δn) with A in units of 1013 cm3/mol • s:
On the Shortwave Emission of Ga-activated Single Crystals of BaCl2
Authors: Tabakova V. , Trifonova R.
Published: February 2015

The luminescence of BaCl2-Ga single crystals at temperatures down to liquid helium under excitation with different energies is studied. The emission consists of several bands, the intensities of which depend on the temperature and the exciting energy. The excitation spectra of the different emission bands measured at 4 K, 78 K and 293 K are also reported.

The results indicate the coexistence of centres of different structure and composition. The Jahn- Teller effect might also take place
Optical Properties of Vanadium Ions in Zinc Sulphide
Authors: Schulz H.-J. , Roussos G. , Biernacki S. W.
Published: February 2015

The luminescence of synthetic ZnS: V crystals is studied at low temperatures (T % 4 K). The emission spectra comprise (i) a structured band centred around v = 5600 cm-1 , assigned to 3T2(F) ->• 3A2(F) transitions of substitutional V3+ (3d2) ions in a tetrahedral field, and (ii) a band around 4800 cm-1 assigned to 4T2(F) -> 4T1(F) transitions of V2+ (3d3) ions. In the range of the narrow no-phonon lines detected with both these emission bands, a temperature rise from 2 to 5 K entails a thermalisation in the population of the spin-orbit multiplets forming the initial states of the corresponding transitions. A third emission band near 3800 cm-1 grows after annealing the crystals in Zn vapour. It is tentatively attributed to 5E(D) -> 5T2(D) transitions of V+ (3d4). A model of one-electron states represents donor-type as well as acceptor-type changes of the vanadium oxidation states, commencing from V2+ , the state with neutral effective charge. The model is substantially founded on the measured excitation spectra of the V3+ and V2+ emission bands, supplemented by transmission spectra. Besides the corresponding broad charge transfer bands, the spectra display a number of structures which are associated with excited states of the ions. These energy levels are approximated in a computation following the strong-field Tanabe-Sugano scheme but in addition allowing for different radial extensions of e- and t2-type wave functions. The method used also includes the possibility of fitting the free-ion levels. Various sets of numerical values are eventually obtained for the crystal-field splitting and the Racah parameters. Some of the levels involved are found to be subject to Jahn-Teller interaction.
High Precision Measurements of the Permittivity of Water in the Microwave Range
Authors: Steinhoff H. J. , Redhardt A. , Lieutenant K. , Chrost W. , Hess G. , Schlitter J. , Neumann H. J.
Published: February 2015

A practical version of a homodyne method for measuring the complex permittivity of high loss liquids at 3 and 9 GHz is described. The systematic errors are discussed in detail, because the homodyne method seems to be suitable as a simple standard method for precise measurements. The results of measurements on water in the temperature range 6 °C-45 °C are presented. The determination of all five parameters of the Debye function is possible. Finally, accuracy limiting factors for the determination of the relaxation parameters are discussed in detail
A Theoretical Study of α-CFnH3-n -substituted Cyclopropyl Cations
Authors: Khalil Salim M. , Jarjis Hayfa M.
Published: February 2015

MINDO-forces calculations are performed, with complete optimization of geometries, on α-Xcyclopropylcations, where X is CF3 , CF2H, and CFH2. It was found that the fluorine atom interacts with the localized empty Pπ-type orbital on α-carbon atom and forms a bridge with an angle 57.1 degree. Calculations also are performed on CF3-cyclopropyl anion and CF2H-cyclopropenyl cation. The fluorine atom in CF3 and CF2H shows no such interaction with the a-carbon atom because there is no localized empty Prc-type orbital
Electromagnetic Field of Accelerated Charges in Inertial Frames with Substratum Flow
Authors: Wilhelm H.E.
Published: February 2015

By means of the generalized Galilei covariant EM field equations, the EM potentials and EM fields of a charged particle moving with an arbitrary nonuniform velocity v(t) in an inertial frame with substratum flow w are calculated. It is shown that the dynamic EM fields are excitations of the EM ether caused by the motion v(t) - w of the charge relative to the wave carrier with velocity w. Qualitatively and quantitatively significant EM inductions and convective deformations of EM fields by the ether flow w exist in inertial frames with ether velocities w~c0 comparable to the velocity of light. For many terrestrial applications, the ordinary Maxwell equations agree in good approximation with the Galilei covariant EM field equations since w/c0~ 10-3 on the earth
Hyperfine Structure in the Rotational Spectrum of tert-Butyl Bromide
Authors: Harder H. , Stahl W. , Dreizler H.
Published: February 2015

We reinvestigated the rotational spectra of tert-butyl bromide (CH3)3C79Br and (CH3)3C81Br, with the high precision of microwave Fourier transform spectroscopy. The rotational and quadrupole coupling constants were improved, the centrifugal distortion and bromine spin-rotation constants were determined
Multipoint Wronskian Method Applied on Model Potentials and Numerical Potential of Triplet H2
Authors: Ergun Yenal , Önder Pamuk H. , Yurtsever Ersin
Published: February 2015

The multipoint Wronskian method is applied to one-dimensional vibrational eigenvalue problems with two different potential functions. Systematic ways of selecting points are discussed. The errors introduced by interpolation methods and the effect of including higher derivatives of the potential are analyzed.
Lattice Vibration Spectra. LX. Lattice Dynamical Calculations on Spinel Type MCr2S4 (M = Mn, Fe, Cd)
Authors: Lutz H. D. , Himmrich J. , Haeuseler H.
Published: February 2015

Lattice dynamical calculations of the spinel type MCr2S4 (M = Mn, Fe, Cd) have been done using various potential models (short-range, rigid-ion, polarizable-ion). The main results are that (i) the vibrational modes (eigenvectors) and potential energy distributions of the Raman and IR allowed phonon modes of the three chromium sulfides are very similar, (ii) the A-X and B-X short-range force constants (referring to AB2X4) strongly depend on the structural parameter u, i.e., the tetrahedral A-X force constants are smaller than the respective octahedral B-X ones opposite to previous calculations on the basis of an ideal spinel structure with u = 0.25, (iii) bending force constants (X-A-X and X-B-X), but not X-X and B-B repulsive forces, are negligible, (iv) in the case of the breathing mode of the tetrahedral AX4 unit (species A1g) the demand on B-X and X-X (stretching and repulsion) forces is larger than that on the A-X force, and (v) the effective dynamic charges of the bivalent metal ions are nearly zero.
Electric field Gradient Modulation by Motion of Lone-Pair Electrons in [(CH3)3S]2MCl6 (M = Pt, Sn) as a Possible Relaxation Mechanism of Chlorine Nuclear Quadrupole Resonance
Authors: Kaga Makoto , Koziol Piotr , Asaji Tetsuo , Nakamura Daiyu
Published: February 2015

The temperature dependence of the chlorine NQR spin-lattice relaxation time T1Q was observed for trimethylsulfonium hexachlorometallates(IV), [(CH3)3S]2MCl6 (M = Pt, Sn), trimethylammonium hexachlorostannate(IV), [(CH3)3NH]2SnCl6, and tetramethylphosphonium hexachlorostannate(IV), [(CH3)4P]2SnCl6. The quadrupolar relaxation in [(CH3)3NH]2SnCl6 and [(CH3)4P]2SnCl6 can be described by the usual librational and reorientational motion of the complex anion at lower and higher temperatures, respectively. Besides T1Q due to these two mechanisms, T1Q minimum was observed at ca. 90 and 120 K for [(CH3)3S]2PtCl6 and [(CH3)3S]2SnCl6, respectively, which is attributable to the electric field gradient modulation by the motion of the [(CH3)3S]+ cation having lone-pair electrons. The activation energies for the isotropic reorientation of the complex anion were determined as 46, 65, 59, and 60 kJ mol -1 for [(CH3)4P]2SnCl6, [(CH3)2NH]2SnCl6, [(CH3)3S]2PtCl6, and [(CH3)3S]2SnCl6, respectively
Partially Invariant Solutions for Two-dimensional Ideal MHD Equations
Authors: Becker D.-A. , Richter E. W.
Published: February 2015

A generalization of the usual method of similarity analysis of differential equations, the method of partially invariant solutions, was introduced by Ovsiannikov. The degree of non-invariance of these solutions is characterized by the defect of invariance d. We develop an algorithm leading to partially invariant solutions of quasilinear systems of first-order partial differential equations. We apply the algorithm to the non-linear equations of the two-dimensional non-stationary ideal MHD with a magnetic field perpendicular to the plane of motion.
Reinvestigation of the Reaction of (NH4)2[Ce(N03)6] with Triphenylphosphine Oxide; the Crystal Structure and Magnetic Properties of mer-Ce(NO3)3(OPPh3)3 • 2 (CH3)2CO
Authors: Lin Jianhua , Hey-Hawkins Evamarie , von Schnering Hans Georg
Published: February 2015

The reaction of (NH4)2[Ce(NO3)6 ] with two equivalents of OPPh3(Ph = C6H5 ) in acetonitrile yields Ce(NO3 ) 4(OPPh3 )2 (1) in high yield, whereas using acetone as solvent affords mer- Ce(NO3 )3(OPPh3)3 • 2(CH3)2CO (2), the yield of which is dependent on the reaction time. A crystal structure determination of 2 shows that the Ce atom is coordinated with three bidentate nitrato groups and three OPPh3 ligands, thus achieving a coordination number of nine. Eight non-coordinating acetone molecules are present in the unit cell. Crystal data (292 K): space group P21/n (no. 14), 0=12.438(2), b = 25.532(4), c = 20.379 (4) Å, β = 96.33(2)°, V = 6432(1) , Z = 4, dcalc = 1.318 g em 3. Due to poor crystal quality the refinement converges at R = 0.11, Rw = 0.09. 2 is paramagnetic, but it does not follow the Curie-Weiss law at low temperature. Therefore crystal field theory was used in order to explain these findings.
Quadrupole Hyperfine Structure in the Rotational Spectra of 1,2- and 1,3-Dichlorobenzene
Authors: Keussen Ch. , Dreizler H. , Merke I.
Published: February 2015

The high resolution of microwave Fourier transform spectroscopy was used to investigate the 35chlorine hyperfine structure of 1,2- and 1,3-dichlorobenzene, C6H4
35Cl2 , very accurately in the rotational spectrum of their ground vibrational state. The careful analysis with a new evaluation program also yielded the off-diagonal element of the coupling tensor. The tensor elements are χaa= -41.1153(35) MHz,χbb = 8.3415(96) MHz, χcc = 32.7738(61) MHz, and χab = ±52.41 (58) MHz for 1,2-dichlorobenzene and χaa= -44.174(12) MHz, χbb= 10.876(12) MHz, χcc = 33.298(12) MHz, and χab= ±48.181(39) MHz for 1,3-dichlorobenzene.
Formula for the Transition Probability Induced by Long-range Potential Terms Varying as R-8 and R-10 for Atom-dimer Collisions
Authors: Hussein Khaled
Published: February 2015

An explicit formula is derived for the transition probability between two different states of the atom-dimer collisional system governed by second-order long-range interaction potential terms varying as R-8 and R-10.
127I-NQR, 119 Sn Mössbauer Effect, and Electrical Conductivity of MSnI3 (M = K, NH4 , Rb, Cs, and CH3NH3 )
Authors: Yamada Koji , Matsui Takashi , Tsuritani Tomoko , Okuda Tsutomu , Ichiba Sumio
Published: February 2015

In a series of MSnI3 compounds (M = K, NH4 , Rb, Cs, CH3NH3) two types of coordination around the central Sn(II) were found by 127I-NQR and powder X-ray diffraction techniques. They are square pyramidal (for M = NH4 , Rb) and octahedral (for M = CH3NH3). CsSnI3 , on the other hand, showed a drastic structural change of the anion at 425 K from a square pyramid to a regular octahedron. Associated with this phase transition, the electrical conductivity increased from 4 x 10-3 S cm-1 to about 102 S cm-1 . This metallic modification was characterized by 127I-NQR and 119Sn Mössbauer spectroscopy.
Narrowing of the 35Cl NQR Lines of Trichloroacetamide Caused by Its Ferroelectric Phase Transition
Authors: Hashimoto Masao , Shono Akiko , Mido Yoshiyuki , Niki Haruo , Hentona Hiroshi , Mano Koichi
Published: February 2015

Dielectric measurements on single crystals and DSC of the title compound (monoclinic, space group P21) revealed a ferroelectric transition at ca. 355 K (ΔH ≈ 0.5 kJ mol-1) Powder x-ray diffraction indicated that the high temperature phase is also monoclinic and the change in volume at the transition is very small. A displacement of hydrogen atoms is considered as responsible for the appearance of ferroelectricity. The 35Cl NQR signals at ca. 77 K were considerably broad, but a drastic narrowing took place after the compound had once experienced the phase transition. A tentative assignment of the NQR spectrum was made from a calculation of the NQR frequencies based on the CNDO/2 method. Another phase transition was evidenced by a small drift of the DSC curve and a slight anomaly of the dielectric behavior around 358 K. The present 1H NMR experiments gave no indication of the onset of torsional motion of the NH2 group reported to occur at ca. 210 K.
NQR and Phase Transitions in Hexachlorocyclopropane Crystal
Authors: Suhara Masahiko , Mano Koichi
Published: February 2015

35Cl NQR and DSC studies on phase transitions in hexachlorocyclopropane (HCCP), C3Cl6 , are reported. It is found that HCCP has three solid phases: A high temperature disordered phase (Phase I) above 301 K (no NQR spectrum was observed); a metastable phase (Phase II), which exhibited 6 NQR lines from 77 to 270 K; a low temperature phase (Phase III) in which a 24-multiplet of 35Cl NQR lines at 77 K, the most complex multiplet spectrum ever reported was observed.

DSC measurement shows a A-type transition at 301 K and a broad transition of very slow rate at 285 K. The structure and mechanism of phase transitions in HCCP crystal are discussed.
Iodine NQR and Phase Transitions in [N(CH3)4]2 ZnI4
Authors: Pirnat J. , Lužnik J. , Trontelj Z.
Published: February 2015

Using a superregenerative NQR spectrometer, the temperature dependence of 127I NQR spectra in [N(CH3)4]2ZnI4 was measured between 167 and 335 K. The measurements confirm two known structural phase transitions at 219 and 257.5 K. The correspondence between the distinct regions of iodine NQR spectra and the crystal structure is discussed. The relation of [N(CH3)4]2ZnI4 to the incommensurate family with the general formula X2YZ4 and the high temperature (paraphase) crystal space group D16
2h (Pmcn) is studied.
Improvement of Bertaut's Method for Calculating Electric Field Gradient
Authors: Nakayama Hirokazu , Saitoa Kazuya , Kishita Michihiko
Published: February 2015

Bertaut's method for calculating the electric field and its gradient is analyzed. The formula for the electric field is always valid, whereas that for the electric field gradient holds only for an infinitely large unit cell. We present a practical method to use the formulae.
Chlorine Nuclear Quadrupole Relaxation Studies on Ionic Dynamics and Phase Transition in NH4AUCl4
Authors: Ishikawa Atsushi , Asaji Tetsuo , Nakamura Daiyu
Published: February 2015

Chlorine NQR frequencies, and NQR spin-lattice and spin-spin relaxation times (T1Q and T2Q) were measured for NH4AuCl4 crystals at various temperatures between 4.2 and 337 K. Each of the two resonance lines observed at room temperature is split into a doublet below Tc = 29 K, indicating a phase transition. A rapid decrease of T1Q above ca. 290 K is attributable to 90° reorientational jumps of the complex anion about its pseudo C4 axis. An activation energy of 80 kJ mol -1 was obtained for this motion. 35Cl T1Q exhibits a minimum at Tc . The T1Q isotope ratio T1Q (37Cl)/ T1Q (35Cl) becomes 1.6 and 1.0 on the high-and low-temperature sides of this minimum, respectively. These results were explained by fluctuations of the electric field gradient produced at the chlorine nuclei by the reorientational jumps of the NH+
4 ions. The motion of the cations is much faster and much slower than the resonance frequencies on the high-and low-temperature sides, respectively. This suggests that the phase transition is of the order-disorder type relating to the orientation of the NH+
4 ion.
Temperature Dependences of NQR Frequencies and Nuclear Quadrupole Relaxation Times of Chlorine in 2,6-Lutidinium Hexachlorotellurate (IV) as Studied by Pulsed NQR Techniques
Authors: Horiuchi Keizo , Shimizu Takashige , Iwafune Hitomi , Asaji Tetsuo , Nakamura Daiyu
Published: February 2015

The temperature dependences of the 35Cl NQR frequencies vQ and the nuclear quadrupole spin-lattice relaxation times T1Q in 2,6-lutidinium hexachlorotellurate (IV) was observed at various temperatures between 80 and 343 K. This crystal undergoes a phase transition at Tc = 229 K. A single and three pairs of 35Cl NQR frequencies were observed above and below Tc , respectively. The hysteresis of the phase transition and a discontinuity in the temperature dependence of the resonance frequencies at Tc indicate that this phase transition is of first order. Although the resonance frequencies of the pairs in the low temperature phase are very close to one another, T1Q and below Tc could be accurately determined by measuring the Fourier transform spectra of each line. Above ca. 250 K, T1Q showed an exponential decrease which is attributable to the overall reorientational motion of [TeCl6]2- with an activation energy of 82 kJ mol-1
New Methods of Nuclear Quadrupole Resonance
Authors: Grechishkin V. S.
Published: February 2015

New NQR methods, developed over the past years, are discussed: 1. Two frequency NQR double resonance, 2. the influence of strong off-resonance combination of rf pulses on demagnetized state in NQR, 3. remote NQR.
Maxwell's Equations and Einstein-Gravity in the Planck Aether Model of a Unified Field Theory
Authors: Winterberg F.
Published: February 2015

In the Planck aether substratum model it is assumed that space is densely filled with both positive and negative Planck masses described by a nonlinear nonrelativistic operator field equation. With-out expenditure of energy this substratum can form a lattice of vortex rings, with the vortex core radius equal the Planck length. The vortex ring radius is determined by a universal minimum energy quantum Reynolds number, making the ring radius and lattice spacing about 10 3 -10 4 times larger than the Planck length. The zero point fluctuations of the Planck masses bound in the vortex filaments become the source of virtual compression waves, which if quantized lead to Newton's law of gravitation, including the correct value for the gravitational constant. This scalar gravitational force couples the vortex rings, which thereby can transmit two types of transverse waves through the vortex lattice. The first type involves the tilting of the vortex rings and can be described by Maxwell's electromagnetic field equations. The second type involves the elliptic deformation of the rings and can be described by Einstein's gravitational field equations. Einstein gravity is therefore explained as resulting from the symmetric, and Maxwell's electromagnetism from the antisymmetric distor-tions of the Planck aether.

Special relativity follows as a dynamic symmetry for objects held together by electromagnetic forces, and general relativity if these objects are placed in a gravitational field. Both special and general relativity, though, turn out to be low energy approximations, breaking down near the Planck scale, eliminating all divergences and singularities.

Finally, the large difference between the electromagnetic and gravitational coupling constants is quantitatively explained to result from the negative masses in the Planck aether.
Investigation of the Microwave Spectrum of cis-Cyclopropyl Carbonyl Chloride-(35Cl); Determination of the Quadrupole Coupling Tensor in its Principal Axes System
Authors: Heldmann C. , Dreizler H. , Schwarz R.
Published: February 2015

The vibrational ground state microwave spectrum of cis-cyclopropyl carbonyl chloride-(35Cl) was investigated in the region from 4 to 40 GHz by microwave Fourier transform (MWFT) spectroscopy. The rotational and fourth order centrifugal distortion constants were determined. The quadrupole hyperfine structure was assigned and the quadrupole coupling constants including the off-diagonal element i ab were evaluated. This leads to a transformation of the quadrupole coupling tensor into its principal axes system.
The Structure of Lithiated Aminonitriles in Solution: Interpretation of their Experimental IR Spectra by Means of ab initio Calculations
Authors: Raabe Gerhard , Zobel Elke , Fleischhauer Jörg , Gerdes Pete , Mannes Dietrich , Müller Edwin , Enders Dieter
Published: February 2015

Quantum chemical calculations of relative energies and vibrational frequencies have been performed in order to elucidate the structure of metalated aminonitriles (1R2RN)3RC2NLi formed upon lithiation of (1R2RN)3RCH-CN in tetrahydrofuran at -78 °C. For the sake of feasibility the calculations have been performed on model compounds where the heavy substituents 1R, 2R and 3R and in some cases even the complete amino group (1R2RN) and 3R have been replaced by hydrogen atoms. In the gasphase a lithium-bridged (nonclassical) monomer, whose lithium atom is within bonding distance to the atoms of the cyano group and the adjacent carbon atom, was found to be about 9 kcal/mol lower in energy than the most stable isomer of the corresponding nitrogen metalated ketenimine with amost linear CNLi moiety. However, the relative stability of the two structures will most likely be reversed under the influence of a solvent (modeled by H20). Dimerization of H2C2NLi, yielding a product of D2h symmetry with a four-membered (LiN)2 ring, turned out to be exothermic by about 41 kcal/mol in the gasphase and 15 kcal/mol when the model solvent is present. While in the case of the lithiated amino ketenimine with almost linear CNLi segment the structure obtained with the semiempirical MNDO method widely parallels the ab initio results, the semiempirical method seems to perform less reliably for the nonclassical monomer. Formation of the trapping products obtained with methyl iodide and acetyl chloride is explained in terms of orbital- and charge control, respectively. According to this analysis, the results of trapping experiments are compatible with presence of a dimer, of a monomer with almost linear CNLi moiety, or of a monomer with lithium in a bridging position. However, comparison of observed and computed vibrational frequencies and of the calculated energies of classical and nonclassical structures led to the conclusion that the observed IR spectra are not due to nonclassical molecules with lithium in a bridging position. Taking into account the results of recent cryoscopic measurements we assign the characteristic absorptions in the experimental IR spectra to keteniminelike monomers and their dimers
Lorentz Transformation of Electromagnetic Systems and the 4/3 Problem
Authors: Comay E.
Published: February 2015

Lorentz transformations of two macroscopic devices are discussed. In each case, the overall momentum flux into every static element of matter vanishes. It is shown that a Lorentz transformation of the energy-momentum 4-vector of each system agrees with special relativity. In particular, using the ordinary definition of 4-momentum of electromagnetic fields, it is proved by means of a particular form of Poincare's stress tensor, that there is no 4/3 factor in the transformation of the entire momentum of a uniformly charged spherical shell
Exchange Forces of Composite Particles in Quantum Field Theory
Authors: Pfister W. , Stumpf H.
Published: February 2015

Quantum fields can be characterized by state functionals and corresponding functional equations. Within this functional representation exchange forces of composite particles are discussed for the case of composite bosons which are bound states of two constituent fermions. The dynamics of these bosons is formulated by means of a weak mapping theorem which establishes a map between the functional equations for the composite boson quantum field and the constituent original fermion quantum field. Evaluation of this theorem leads to expressions which can be identified as quantum field theoretic "direct" forces and exchange forces for or between composite particles. By some theorems the exchange forces are evaluated and an estimate for them is given. The expressions for the direct forces correspond to those which were already derived in previous papers to discuss composite particle dynamics.
Polarization Studies of the Electronic Minority Charge Carriers in Ag+ -ß"-Alumina
Authors: Weppner Werner , Liu Jun
Published: February 2015

The partial electronic conductivity of Ag+-ß"-alumina was determined in the temperature range 180-200 °C, using Wagner's asymmetric galvanic polarization cell Ag| Ag+-ß"-alumina | Pt. The electron conductivity is 4.5 x 10-8 Ω-1cm-1, while the hole conductivity is about seven orders of magnitude lower at the silver activity aAg =1at 200 °C. These results are compared with earlier data on ß/ß"-alumina. The conduction mechanism and the effect of the electronic conductivity on the application of Ag+-ß"-alumina are discussed
Disturbances in Pipe Flow Excited by Magnetic Fields
Authors: Brösa U.
Published: February 2015

Defined disturbances of laminar flow in a pipe can be excited by magnetic fields. This is important for investigations concerning the onset of turbulence in a pipe. A theory of these disturbances is derived and thus a criterion established to discriminate the induction of the so-called mothers from the excitation of daughters. The conditions to optimize the effects and the inferences for the experimental setup are discussed
Heteroclinic Bifurcations and Invariant Manifolds in Rocking Block Dynamics
Authors: Bruhn B. , Koch B. P.
Published: February 2015

A simple model of rigid block motion under the influence of external perturbations is discussed. For periodic forcings we prove the existence of Smale horseshoe chaos in the dynamics. For slender blocks a heteroclinic bifurcation condition is calculated exactly, i.e. without using perturbation methods. That means that our results are valid for arbitrary excitation amplitudes. Furthermore, analytical formulas for the first pieces of the stable and unstable manifolds are derived not only for periodically but also for transiently driven systems. In the case of small excitation and damping the Melnikov method is used to treat the full nonlinear problem
Determination of Unstable Limit Cycles in Chaotic Systems by the Method of Unrestricted Harmonic Balance
Authors: Neymeyr Klaus , Seelig Friedrich Franz
Published: February 2015

The method of unrestricted harmonic balance (UHB) which is a generalization of the old method of harmonic balance and that was developed in preceding papers, is mathematically refined and applied to the evaluation of unstable limit cycles. The method is demonstrated for the case of the best investigated chaotic system, namely the Lorenz system. Some representative results are given
Particular Vibration Spectrum of Antimony Trichloride Caused by Bond Fluctuation
Authors: Friedewold Hans , Brockner Wolfgang
Published: February 2015

Vibration spectra of solid and molten antimony trichloride were recorded. In the solid state, vibration frequencies in addition to those of the SbCl3 molecules with their C3, symmetry indicate bond fluctuations according to 2 SbCl3 ⇄Sb++ SbCl6
-.
The Microwave Spectrum of 4-Methylisothiazole
Authors: Nicolaisen H.-W. , Grabow J.-U. , Heineking N. , Stahl W.
Published: February 2015

The microwave spectrum of 4-methylisothiazole was assigned by means of a pulsed molecular beam microwave Fourier transform spectrometer. Analysis of the spectrum yielded the rotational constants .4 = 7370.642(31) MHz, B = 2515.8461 (30) MHz, C = 1897.2863(33) MHz, a threefold barrier to internal rotation of the methyl group of V3 = 3170.81 (130) GHz≙ 105.7669(430) cm-1, a momentum of inertia of the methyl group of Iα = 3.16769(130) amu · Å2 and an angle between internal rotor axis and principal a-axis of Θ= 5.406(38)°. The nitrogen quadrupole coupling constants were determined to be χ+ = χbb + χcc = 1.4822(14) MHz, χ -= χbb-χcc = - 1.4353(25) MHz and χab= - 3.16(12) MHz.
On the Characterization of the Scaling Behavior of Dissipative Dynamical Systems through a Generalized Entropy
Authors: Stoop R. , Parisi J. , Brauchli H.
Published: February 2015

Different aspects of the scaling behavior of a dissipative dynamical system arc obtained in a straightforward way from the associated generalized entropy function which, in this way, embodies the relevant information on the scaling behavior of the system. This is demonstrated by the application of the thermodynamic formalism to two model systems for each of which, however, a specific numerical approach must be followed in order to overcome the numerical problems.
Geodesic Motion in Trivializable Gauge Fields
Authors: Heck T. , Sorg M.
Published: February 2015

The geodesic problem is studied for a Riemannian structure, which is generated by an SO(4) trivializable gauge field. The topological and elliptic geometric defects of such a structure act as attractors for the geodesic curves
Molecular g-Values, Magnetic Susceptibility, Anisotropics, Second Moments of the Electronic Charge Distribution. Molecular Electric Quadrupole Moment, and 14N Nuclear Quadrupole Coupling of Nitroethylene, CH2 = CH - N02
Authors: Spiekermann J. , Sutter D. H.
Published: February 2015

The high-field linear and quadratic Zeeman effect has been observed in nitroethylene. The spectrum is complicated by the presence of 14N nuclear quadrupole coupling which was reanalyzed from low-J zero-field transitions observed under high resolution. Our 14N quadrupole coupling constants are Xaa = -0.8887(18) MHz, Xbb = +0.0429(29) MHz, Xcc = +0.8458(29) MHz (c-axis perpendicular to the molecular plane). Our g-values and magnetic susceptibility anisotropics, fitted to the observed high-field Zeeman multiplets, are gaa = -0.15 985(39), -0.07197(31), gcc= -0.01080(32), 2ξaa-ξbb-ξcc= + 19.07(43) * 10-6 erg * G-2 * mole-1 and 2ξbb- ξcc- ξaa = + 29.67(53) -10-6 erg * G-2 * mole-1 . From them, the anisotropics in the second moments of the electronic charge distribution and the components of the molecular electric quadrupole moment with respect to the principal inertia axes system follow as  - = +36.55(7)Å2 ,  - = +23.58(9) Å2, - = -60.14(8) Å2, Qaa= -0.59(29) D * Å, Qbb = +0.07(36) D * Å, and Qcc = +0.52(46) D * Å. The 14N quadrupole coupling constants, the anisotropics in the second electronic moments and the quadrupole moments are compared to the corresponding Hartree-Fock SCF values calculated with the Gaussian 88 program. The discrepancy between the experimental values and the ab initio values is considerably larger than found earlier in a similar investigation of a group of imines
Photophysical Properties of Some Quindoline Bases and their Salts
Authors: Nikolov Peter , Stoyanov Stefan , Jezerskaite Angele
Published: February 2015

The title compounds are used as sensitizers in electrophotography. The dependence of their absorption and luminescence characteristics on the substituent, medium and temperature is investigated. The influence of various factors on the equilibrium base - salt in solution is elucidated. On the basis of changes in the absorption spectra with concentration the equilibrium constants Kq are determined
Hydration of the Ammonium Ion: Monte Carlo Simulation
Authors: Noto R. , Martorana V. , Migliore M. , Fornili S. L.
Published: February 2015

A Monte Carlo simulation of ammonium aqueous solution at infinite dilution shows that this ion is on the average rather loosely bonded to three of the fourteen water molecules present in its first hydration shell. This result agrees with conclusions suggested by recent experiments on the rotational mobility of ammonium in liquid water.