 181  Author
 H. G. Kreul, R. Waldinger, A. Würflinger  Requires cookie*   Title
 Differential Thermal Analysis and Dielectric Studies on Neopentanol under Pressure    Abstract
 Differential thermal analysis (DTA) and dielectric measurements have been performed on 2,2dimethyllpropanol (neopentanol) up to 200 MPa. Neopentanol exhibits at least one orientationally disordered (ODIC) phase (solid I) that transforms at lower temperatures to a nonplastic phase (solid II). There is evidence of a further ODIC phase denoted as solid I'. The pressure dependence of the phase transitions and the dielectric behaviour up to frequencies of 13 MHz are described. Activation enthalpies and volumes are derived from the dielectric relaxation time and compared with results for other alcohols.   
Reference
 Z. Naturforsch. 47a, 1127—1134 (1992); received July 27 1992   
Published
 1992   
Keywords
 High pressure, DTA, Phase transitions, Dielectric constant, and relaxation   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1127.pdf    Identifier
 ZNA199247a1127    Volume
 47  
182  Author
 S. V. Stockhausen, Hornhardt  Requires cookie*   Title
 M    Abstract
 The dielectric spectra of liquid cyclopentanol, cyclohexanol, cycloheptanol and cyclooctanol are reported for frequencies up to 72 GHz and temperature 20 (cyclohexanol solid), 30 and 40 °C. The absorption spectra are peculiar in exhibiting a remarkably developed high frequency shoulder which is attributed to single molecule and internal motion, while the principal absorption is due to association as with other alcohols.   
Reference
 Z. Naturforsch. 47a, 1135—1137 (1992); received August 11 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1135.pdf    Identifier
 ZNA199247a1135    Volume
 47  
183  Author
 M. Klatt, M. Röhrig, H. Gg, Wagner  Requires cookie*   Title
 About the Radical Formation in the Pyrolysis of Formic Acid at High Temperatures    Abstract
 The formation of radicals in the HCOOH pyrolysis was investigated in the temperature and density range between 1450 and 2450 K and 2 • 10~ 6 and 1.2 • 10" 5 mol /cm 3 , respectively. The small amount of radicals found indicates that a radical forming reaction path in the formic acid pyrolysis is smaller than 0.2% of the total decomposition rate.   
Reference
 Z. Naturforsch. 47a, 1138—1140 (1992); received September 12 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1138.pdf    Identifier
 ZNA199247a1138    Volume
 47  
184  Author
 Ilona Merke, Helmut Dreizler  Requires cookie*   Title
 Quadrupole Hyperfine Structure in the Rotational Spectra of Sulfur Dichloride    Abstract
 The nuclear quadrupole coupling of [ 35 C1, 35 C1]and [ 35 Cl, 37 Cl]sulfur dichloride was investigated using waveguide microwave Fourier transform (MWFT) spectroscopy. The analysis was performed with direct diagonalization of the Hamilton matrix. Due to some measured transitions with near degeneracy it was possible to determine the off diagonal elements xab °f th e quadrupole coupling tensor with high accuracy. S 35 C1 2 : x afl (35 Cll) = x aa (35 C12) 38.671(11) MHz, Zcc (35 CU) = Xcc (35 C\2) = 47.7945(66) MHz, Zflfc (35 Cll) = —x ab (C\2) = ± 53.76(23) MHz. S 35 C1 36 C1: * aa (35 Cl) = 37.756(13) MHz, x cc (35 Cl) = 47.7915(75) MHz, X ah (35 Cl) = ± 54.018(83) MHz, * aa (35 Cl) 31.217(13) MHz, X cc (37 C1) = 37.6759(66) MHz, x ab (31 C1) = + 42.285(98) MHz. We also determined the quadrupole coupling constants in their principal axes system. In comparison with the restructure the zaxis of the coupling tensor was found to be tilted 1.3° out of the SCl bond axis.   
Reference
 Z. Naturforsch. 47a, 1141—1144 (1992); received August 26 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1141.pdf    Identifier
 ZNA199247a1141    Volume
 47  
185  Author
 H. D. Lutz, M. Schmidt  Requires cookie*   Title
 Lattice Vibration Spectra. LXXV. IR Single Crystal Reflection Spectra of Sr(C10 3 ) 2    Abstract
 Polarized infrared reflection spectra of Sr(C10 3) 2 singlecrystal plates are recorded and analysed for the frequencies of the transversal and longitudinal optical zonecentre phonon modes and other oscillator parameters by KramersKronig analyses and both the classical 3 parameter (dielectric sumfunction) and the 4 parameter (factorized form) oscillatorfit methods. The frequencies computed are compared with the results of previous singlecrystal Raman studies. Because of the great distortion of the C10 3 ions (site symmetry CJ, no intraionic coupling of the CIO vibrations to symmetric (vj and asymmetric (v 3) stretching modes occurs. The TO/LO splittings of respective CIO unitcell group modes rank like the vector elements of the corresponding CIO bonds with respect to the crystal axes.   
Reference
 Z. Naturforsch. 47a, 1145 (1992); received August 17 1992   
Published
 1992   
Keywords
 Strontium chlorate, IR reflection spectra, Oscillatorfit calculations, LO phonon modes   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1145.pdf    Identifier
 ZNA199247a1145    Volume
 47  
187  Author
 Ilona Merke, Helmut Dreizler  Requires cookie*   Title
 Quadrupole Hyperfine Structure in the Rotational Spectra of Sulfuryl Chloride    Abstract
 The nuclear quadrupole coupling of [ 35 C1, 35 C1]and [ 35 Cl, 37 Cl]sulfuryl chloride, S0 2 C1 2 was investigated using waveguide microwave Fourier transform (MWFT) spectroscopy. The analysis was performed with direct diagonalization of the Hamiltonian matrix. It was possible to determine the complete coupling tensor with high accuracy. S0 2 35 C1 2 : * aa (35 Cll) = * aa (35 C12) = 33.049(6) MHz, Xcc (35 C11) = x cc (35 C12) = 40.356 (9) MHz, Zfli (35 CU) = x afc (35 C12) = + 52.67 (63) MHz. S0 2 35 C1 37 C1: x aa (35 Cl)= 29.582(17) MHz, * cc (35 Cl) = 40.340(25) MHz, Zafc (35 Cl)= +52.3(14) MHz, Xflfl (37 Cl)= 28.723(18) MHz, * cc (37 Cl) = 31.822(28) MHz, * ai ,(37 Cl) = + 37.3(19) MHz. We also determined the quadrupole coupling constants in their principal axes system. In comparison with the structure, the zaxis of the coupling tensor was found to be tilted 2.0° out off the SCl bond axis.   
Reference
 Z. Naturforsch. 47a, 1153—1156 (1992); received September 12 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1153.pdf    Identifier
 ZNA199247a1153    Volume
 47  
189  Author
 H. Kötz  Requires cookie*   Title
 A Technique to Classify the Similarity Solutions of Nonlinear Partial (Integro)Differential Equations. I. Optimal Systems of Solvable Lie Subalgebras    Abstract
 Lie group analysis is a powerful tool for obtaining exact similarity solutions of nonlinear (integro) differential equations. In order to calculate the groupinvariant solutions one first has to find the full Lie point symmetry group admitted by the given (integro)differential equations and to determine all the subgroups of this Lie group. An effective, systematic means to classify the similarity solutions afterwards is an "optimal system", i.e. a list of groupinvariant solutions from which every other such solution can be derived. The problem to find optimal systems of similarity solutions leads to that to "construct" the optimal systems of subalgebras for the Lie algebra of the known Lie point symmetry group. Our aim is to demonstrate a practicable technique for determining these optimal subalgebraic systems using the invariants relative to the group of the inner automorphisms of the Lie algebra in case of a finitedimensional Lie point symmetry group. Here, we restrict our attention to optimal subsystems of solvable Lie subalgebras. This technique is applied to the ninedimensional real Lie point symmetry group admitted by the twodimensional nonstationary ideal magnetohydrodynamic equations.   
Reference
 Z. Naturforsch. 47a, 1161—1173 (1992); received July 9 1992   
Published
 1992   
Keywords
 Group theory, Magnetohydrodynamics, Compressible flows   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1161.pdf    Identifier
 ZNA199247a1161    Volume
 47  
190  Author
 BertholdGeorg Englert, MarianO. Scully, Georg Süssmann, Herbert Walther  Requires cookie*   Title
 Surrealistic Böhm Trajectories    Abstract
 A study of interferometers with onebit whichway detectors demonstrates that the trajectories, which David Böhm invented in his attempt at a realistic interpretation of quantum mechanics, are in fact surrealistic, because they may be macroscopically at variance with the observed track of the particle. We consider a twoslit interferometer and an incomplete SternGerlach interferometer, and propose an experimentum crucis based on the latter.   
Reference
 Z. Naturforsch. 47a, 1175—1186 (1992); received September 22 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1175.pdf    Identifier
 ZNA199247a1175    Volume
 47  
191  Author
 T. Schilling, B. Tesche, G. Lehmpfuhl  Requires cookie*   Title
 Reconstructed Au (100) Surface Imaged with Scanning Tunneling Microscopy in Air    Abstract
 Scanning tunneling microscopy (STM) of Au(100) was performed in air with a NanoScope II. Regions of 150 x 150 nm with atomatically flat areas fragmented by atomic steps were observed. The reconstructed (100) surface, deformed to a twisted hexagon with an interatomic distance of 0.27 + 0.02 nm, could be seen and a corrugation of about 0.05 nm depth was measured. These results are in good agreement with Reflection Electron Microscopy measurements and STM investigations in UHV.   
Reference
 Z. Naturforsch. 47a, 1187—1190 (1992); received September 19 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1187.pdf    Identifier
 ZNA199247a1187    Volume
 47  
192  Author
 YuA. Babanov, A. F. Sidorenko, V. R. Shvetsov, M. Bionducci, G. Licheri, G. Navarra, A. L. Ageev, V. V. Vasin  Requires cookie*   Title
 Combination of EXAFS and Differential Anomalous Xray Scattering for Studying Ni 2 Zr Amorphous Alloy    Abstract
 In this paper we report a first application of the new idea of combining EXAFS and differential anomalous scattering techniques to obtain partial distribution functions for a binary amorphous sample. This method has been successfully employed in extracting NiNi and NiZr pair distribution functions for Ni 2 Zr prepared by mechanical alloying. A comparison with results from previous studies is also reported.   
Reference
 Z. Naturforsch. 47a, 1191—1196 (1992)   
Published
 1992   
Keywords
 Metallic glasses, Synchrotron radiation, Partial pair distribution functions   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1191.pdf    Identifier
 ZNA199247a1191    Volume
 47  
193  Author
 Wolfram Bodenmüller, Andreas Ruoff, Laurent Manceron  Requires cookie*   Title
 FTIR Study of the v 12 and the v 12 + v 14 — v 14 Bands of 1,3,5Triazine Near 740 cm 1    Abstract
 The infrared spectrum of the v 12 fundamental and its accompanying hot band v 12 + v 14 — v 14 of triazine has been measured by means of a Fourier transform spectrometer with a resolution of about 0.0023 cm" 1 . A total of about 2779 rovibrational transitions has been assigned. The ground state constants have been considerably improved whilst the parameters for the excited states tf 12 =l, i; 14 = l and tf 12 =i> 14 = l have been obtained for the first time. The standard deviations were 2.92 • 10" 4 cm" 1 for the ground state constants and 1.53 • 10" 4 cm 1 for the excited state parameters of v 12 showing the latter to be unperturbed. The upper state of the hot band v 12 + v 14 — v 14 was found to be perturbed by an accidental resonance.   
Reference
 Z. Naturforsch. 47a, 1197—1203 (1992); received October 20 1992   
Published
 1992   
Keywords
 1, 3, 5triazine, High resolution FTIR spectroscopy, Ground state constants Fundamental constants, Hot band constants   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1197.pdf    Identifier
 ZNA199247a1197    Volume
 47  
194  Author
 A. Kawski, B. Kukliński, A. Kubicki  Requires cookie*   Title
 Isomerization of Diphenyl Polyenes. Part III. Absorption and Fluorescence Properties of l,4Diphenyll,3butadiene in Polyvinyl alcohol) Film    Abstract
 The effect of temperature on the absorption and fluorescence properties of l,4diphenyll,3butadiene (DPB) in polyvinyl alcohol) film (PVA) was investigated in the range from 293 to 423 K. Upon heating above 353 K, the optical density in the long wavelength region (at 339 nm) increases five times only, whereas for l,6diphenyll,3,5hexatriene (DPH) and l,8diphenyll,3,5,7octatetraene (DPO) ten and twenty times, respectively. However, the total quantum yield ($ F = 0.68) at 293 K is greater than that for the transtrans form (<P F = 0.63) and decreases with growing temperature. Both this effect and broadening effect in the fluorescence band at 293 K evidence the existence of two emission centres, i.e. the transtrans and cistrans conformers.   
Reference
 Z. Naturforsch. 47a, 1204—1210 (1992); received November 11 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1204.pdf    Identifier
 ZNA199247a1204    Volume
 47  
196  Author
 F. Winterberg  Requires cookie*   Title
 Cosmological Implications of the Planck Aether Model for a Unified Field Theory    Abstract
 In the previously proposed Planck aether model of a unified theory, the vacuum ground state consists of a dense assembly of positive and negative Planck masses obeying an exactly nonrelativistic law of motion. The Planck aether is superfluid, and it can without expenditure of energy form a tangle of quantized vortex filamants permitting the transmission of two types of waves: One associated with a symmetric displacement of the vortex lattice leading to gravitational waves, and one associated with an antisymmetric displacement leading to electromagnetic waves. Dirac spinors are explained in this model as excitons made up from positive and negative energy resonances of the vortex lattice. Because the number of positive and negative Planck masses is assumed to be equal, the cosmological constant is equal to zero. With the Dirac spinors formed as bound states from the Planck aether, the sum of the positive kinetic energy and negative gravitational energy must remain exactly equal to zero, resulting in ß = l as the exact value for the cosmological mass parameter. To make up for the unobserved missing mass, estimated to be about 10 times larger than the baryonic mass, it is conjectured that this mass consists of rotons, which in the superfluid Planck aether would come from the cutoff of the energy spectrum near the Planck energy. Because of their unusual dispersion relation, rotons possess a large momentum, even if their velocity vanishes. They are, for this reason, a promising candidate for the nonbaryonic dark matter, combining properties of hot and cold dark matter. The critical value Q= 1 requires that the number density of the rotons is equal to n r cs 2 x 10" 25 cm 3 . This value corresponds to an average distance of separation between the rotons of the order n~ 1/3 ~ 6000 km. The small number of rotons per unit volume combined with their weak gravitational coupling constant would make it difficult to detect them directly, but the gravitational field these roton masses generate in the vicinity of galaxies could explain the observed flat rotation curves of disc galaxies. Finally, because the gravitational waves have a cutoff at the vortex lattice scale at 10 15 10 16 GeV, there can be no singularity in the course of a gravitational collapse, as it happens for solutions of Einstein's gravitational field equations. A generalization of Einstein's gravitational field Lagrangian, taking into account the existence of a smallest wave length, rather predicts a conversion of all mass into electromagnetic (or gravitational) radiation in approaching the singularity. The predicted conversion of mass into radiation in the course of gravitational collapse may provide an explanation for the large energy release of quasars.   
Reference
 Z. Naturforsch. 47a, 1217—1226 (1992); received June 15 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1217.pdf    Identifier
 ZNA199247a1217    Volume
 47  
197  Author
 R. C. Sharma, Sunil  Requires cookie*   Title
 RayleighTaylor Instability of a Partially Ionized Plasma in a Porous Medium in Presence of a Variable Magnetic Field    Abstract
 The RayleighTaylor instability of a partially ionized plasma in a porous medium is considered in the presence of a variable magnetic field perpendicular to gravity. The cases of two uniform partially ionized plasmas separated by a horizontal boundary and exponentially varying density, viscosity, magnetic field and neutral particle number density are considered. In each case, the magnetic field succeeds in stabilizing waves in a certain wavenumber range which were unstable in the absence of the magnetic field, whereas the system is found to be stable for potentially stable configuration/stable stratifications. The growth rates both increase (for certain wave numbers) and decrease (for different wave numbers) with the increase in kinematic viscosity, medium permeability and collisional frequency. The medium permeability and collisions do not have any qualitative effect on the nature of stability or instability.   
Reference
 Z. Naturforsch. 47a, 1227—1231 (1992); received July 8 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1227.pdf    Identifier
 ZNA199247a1227    Volume
 47  
199  Author
 A. L. AlexeIonescu, R. Barberi, G. Barbero, T. Beica, R. Moldovan, I.N F M  Requires cookie*   Title
 Surface Energy for Nematic Liquid Crystals: A New Point of View    Abstract
 The surface energy of nematic liquid crystals is deduced from a phenomenological point of view. The idea of an easy surface tensor order parameter is proposed. An expression similar to a Landau expansion for the free energy of a system characterized by two order parameters is deduced and analysed. An interpretation similar to the one usually accepted for magnetic materials is given. The possibility of surface transitions induced by temperature is discussed. PACS 61.30 V, 64.70 Md, 61.30 Gd.   
Reference
 Z. Naturforsch. 47a, 1235—1240 (1992); received August 19 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1235.pdf    Identifier
 ZNA199247a1235    Volume
 47  
200  Author
 Michael Krüger, Ilona Merke, Helmut Dreizler  Requires cookie*   Title
 Dipole Moment and High Resolution Rotational Spectrum of Fluorocyanoacetylene, FCCCN    Abstract
 The title molecule was produced in a dc discharge from pentafluoro benzonitrile, C 6 F 5 CN. The dipole moment of fluorocyanoacetylene was found to be 3.05(15) D from the Stark effect. The 14 N nuclear quadrupole coupling constant % zz ~ — 4.2513 (47) MHz was determined from high resolution rotational spectra obtained with a pulsed nozzle molecularbeam microwave Fourier transform spectrometer.   
Reference
 Z. Naturforsch. 47a, 1241—1242 (1992); received September 18 1992   
Published
 1992   
Similar Items
 Find   DEBUG INFO
    TEIXML for
 default:Reihe_A/47/ZNA199247a1241.pdf    Identifier
 ZNA199247a1241    Volume
 47  
