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1985 (209)
41Author    G. Bestmann, H. DreizlerRequires cookie*
 Title    A Redetermination of the Barrier to Internal Rotation of 2-Fluoropropene  
 Abstract    We present the determination of the methyl barrier to internal rotation from the rotational spectrum in the ground state of 2-fluoropropene. A complete set of barrier parameters could be determined. The results are compared with those of 2-chloro-and 2-bromopropene, achieved by the same technique and evaluation method. 
  Reference    Z. Naturforsch. 40a, 267—270 (1985); received January 15 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0267 
 Volume    40 
42Author    G. Bestmann, W. Lalowski, H. DreizlerRequires cookie*
 Title    Determination of a High Barrier Hindering Internal Rotation from the Ground State Spectrum. The Methylbarrier of Propane  
 Abstract    The internal rotation barrier V 3 , the moment of inertia of the methyl tops and the angle be-tween the two internal rotation axes were determined from the torsional fine structure of the rotational spectrum in the torsional ground state. A tilt angle of 1.4° of the methyl groups toward each other results. 
  Reference    Z. Naturforsch. 40a, 271—273 (1985); received January 15 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0271 
 Volume    40 
43Author    PaulK. Burkert, DagmarG. KlobasaRequires cookie*
 Title    Anomalous Temperature Dependence of the 127 I-Quadrupole Coupling in (C6H5)4PI04, (C6H5)4ASI04 and (C6H5)4SbI04  
 Abstract    On measuring second order quadrupole effects in 127 I solid state NMR, new anomalous tem-perature coefficients of the quadrupole interaction were observed in tetraphenylphosphonium-, tetraphenylarsonium-and tetraphenylstibonium metaperiodate. The relevance of possible mecha-nisms like breakdown of d^ —backbonding, negative pressure coefficients, charge transfer, orientational change of the electric field gradient tensors, and influence of reorientational motions is discussed for these compounds. 
  Reference    Z. Naturforsch. 40a, 274—278 (1985); received December 20 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0274 
 Volume    40 
44Author    Walter FabianRequires cookie*
 Title    Photochemische (2 + 2) Cycloadditionen an die C=N Doppelbindung — eine theoretische Untersuchung zur Regioselektivität  
 Abstract    Photochemical (2 + 2) Cycloadditions to the C = N Double Bond -a Theoretical Study on the Regioselectivity Based on quantum chemical calculations (INDO/S and ab initio) the remarkable regioselec-tivity observed with the photochemical (2 + 2) cycloaddition of olefins to the C=N double bond is interpreted by means of perturbational molecular orbital theory. In each case the predic-tions concerning the most favourable regioisomer are completely in agreement with experimental findings. 
  Reference    Z. Naturforsch. 40a, 279—282 (1985); eingegangen am 17. Dezember 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0279 
 Volume    40 
45Author    R. Grosescu, U. HaeberlenRequires cookie*
 Title    The Nuclear Magnetic Shielding of the 19 F-Nuclei in KZnF 3  
 Abstract    Using solid state multiple pulse techniques the magnetic shielding tensors a of the 19 F nuclei in a single crystal of KZnF 3 have been measured. The F~-site symmetry in KZnF 3 , D 4h , allows axial anisotropy of a and determines fully the principal shielding directions. Using CaF 2 as the reference compound, the average shielding is + 85 ppm and the shielding anisotropy is + 18.4 ppm. These results are discussed in terms of shielding contributions from (a) the closed shell electrons of the F~-ion whose shielding is considered, (b) the closed shell electrons of the neighbouring metal and fluorine ions and (c) weak admixture of covalency to the predominantly ionic Zn ++ —F~ bonding. 
  Reference    Z. Naturforsch. 40a, 283—293 (1985); received December 20 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0283 
 Volume    40 
46Author    H. StumpfRequires cookie*
 Title    Effective Interactions of Relativistic Composite Particles in Unified Nonlinear Spinor-Field Models. Ill "  
 Abstract    Unified nonlinear spinor field models are selfregularizing quantum field theories in which all observable (elementary and non-elementary) particles are assumed to be bound states of fermionic preon fields. Due to their large masses the preons themselves are confined. In preceding papers a functional energy representation, the statistical interpretation and the dynamic equations were derived. In this paper the dynamics of composite particles is discussed. The composite particles are defined to be eigensolutions of the diagonal part of the energy representation. Corresponding calculations are in preparation, but in the present paper a suitable composite particle spectrum is assumed. It consists of preon-antipreon boson states and three-preon-fermion states with corresponding antifermions and contains bound states as well as preon scattering states. The state functional is expanded in terms of these composite particle states with inclusion of preon scattering states. The transformation of the functional energy representa-tion of the spinor field into composite particle functional operators produces a hierarchy of effective interactions at the composite particle level, the leading terms of which are identical with the functional energy representation of a phenomenological boson-fermion coupling theory. This representation is valid as long as the processes are assumed to be below the energetic threshold for preon production or preon break-up reactions, respectively. From this it can be concluded that below the threshold the effective interactions of composite particles in a unified spinor field model lead to phenomenological coupling theories which depend in their properties on the bound state spectrum of the self-regularizing spinor theory. PACS 11.10 Field Theory PACS 12.35 Composite Models of Particles 8. Evaluation of Cluster Interactions 
  Reference    Z. Naturforsch. 40a, 294—301 (1985); received September 15. 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0294 
 Volume    40 
47Author    G. Metsch, W. Bauhofer, A. SimonRequires cookie*
 Title    Die Reflektivität von Rubidium-und Cäsium-Suboxiden  
 Abstract    The Reflectivity of Rb and Cs Suboxides The reflectivity of single crystals of the alkali metal suboxides Cs 7 0, Cs 4 0, Csn0 3 und Rb 9 0 2 has been measured with linearly polarised light in the range from 0.4 to 5 eV. The plasma frequency is derived as a function of the oxygen content by means of Kramers-Kronig analysis of the data. A Drude-Lorentz fit allows the assignment of additional structures in the spectra. These structures are discussed in terms of surface plasma oscillations, inter-band transitions from the 02p band and "void modes". 
  Reference    Z. Naturforsch. 40a, 303—312 (1985); received January 24 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0303 
 Volume    40 
48Author    A. Kawski, Z. Kojro, A. KubickiRequires cookie*
 Title    Influence of Quenching upon the Rotational Depolarization of Fluorescence  
 Abstract    The theory of the rotational depolarization of fluorescence taking into account the inertial effect was verified experimentally on the example of 2,2'-p-phenylenebis(5-phenyloxazole) (POPOP), 2,2'-p-phenylenebis(4-methyl-5-phenyloxazole) 2MPOPOP), p-bis[2-(5-a-naphthylox-azolyl)]-benzene (a-NOPON), diphenylenestilbene (DPS) and 1,6-diphenylhexatriene (DPH) in cyclohexane by the method of quenching with nitrobenzene. The volumes obtained for the centers and moments of inertia are lower than those obtained by the use of solvents of different vis-cosities, but they still refer to the solvated molecules. 
  Reference    Z. Naturforsch. 40a, 313—316 (1985); received September 29 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0313 
 Volume    40 
49Author    G. Gauglitz, R. Goes, W. Stooß, R. RaueRequires cookie*
 Title    Determination of Partial Photochemical Quantum Yields of Reversible Photoisomerizations of Stilbene-1 Derivatives  
 Abstract    Dedicated to Prof. Schulte-Frohiinde on the occasion of his 60th anniversary Partial photochemical quantum yields of derivatives of stilbene-1 can be determined by a new microprocessor controlled apparatus for the measurement of fluorescence intensities in depen-dence on reaction time. The consecutive photoproducts must not be known. Some of the 20 examined dyes show laser activity combined with relatively high photostability. Photochemical quantum yields and laser peak power were determined in dependence on structure. A detailed knowledge of the photokinetic parameters gives the opportunity to obtain indications of efficient and photostable laser dyes. 
  Reference    Z. Naturforsch. 40a, 317—323 (1985); received December 10 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0317 
 Volume    40 
50Author    Masao Hashimoto, Norbert Weiden, Alarich WeissRequires cookie*
 Title    The C—CI Bonds in a-2,4,6-tris(trichIoromethyl)-l,3,5-trioxane, a-Parachloral, (Cl 3 CCHO) 3 . A 35 C1-NQR Single Crystal Study  
 Abstract    By single crystal 35 C1-NQR Zeeman spectroscopy, the five independent 35 C1 nuclear quadru-pole coupling tensors in a-parachloral, (Cl 3 CCHO) 3 , have been studied at 24 ± 2 °C. The direc-tions of the electric field gradient (EFG) tensor components have been determined. The principal axes are within ± 0.8° parallel to the C-Cl bond directions found by X-ray diffraction. Very small asymmetry parameters in the range 0.002 ^ rj ^ 0.046 are characteristic for the EFG tensors of chlorine atoms bound to carbon atoms in aliphatic systems. The five nuclear quadru-pole coupling constants are in the range 76.752 ^ e 2 qQh~ x /MRz ^ 78.155. The orientation of the principal axes 4> xx and <P yy can be correlated to the molecular structure. 
  Reference    Z. Naturforsch. 40a, 324—334 (1985); received January 16 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0324 
 Volume    40 
51Author    P. C. SchmidtRequires cookie*
 Title    On the Chemical Bonding in the Intermetallic B32-Type Compounds LiMe (Me = Al, Zn, Ga, Cd, and In)  
 Abstract    The electronic charge distributions in the binary intermetallic B32 phases LiMe with Me = Zn, Cd. AI, Ga and In have been calculated by the relativistic augmented plane wave method. It is found that the character of the contribution from the various electron bands to the chemical bond is different for the lower valence bands and for the higher valence-conduction bands. The lower valence bands are occupied by two electrons per formula unit LiMe and are pre-dominantly of covalent s-p-type, formed by the diamond-like sublattice of the Me atoms. For all compounds the percentage p-like character is smaller than for the sp 3 hybrid within the molecular orbital picture. The valence bands above the covalent bands are s-p-like bands with enhanced metallic character. Besides a large covalent contribution to the chemical bond in the intermetallic B32-type phases, a charge transfer from the lithium atoms to the lib and Ilia elements is found. The amount of charge transfer is distinctly smaller than one electron per formula unit LiMe. It is shown that the charge transfer is correlated to the differences in the electronegativities of the corresponding atoms. 
  Reference    Z. Naturforsch. 40a, 335—346 (1985); received January 29 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0335 
 Volume    40 
52Author    Shin-Ichi Fukada, Ryuichi Ikeda, Daiyu NakamuraRequires cookie*
 Title    NMR and Differential Scanning Calorimetry Studies of Molecular Motion and Phase Transition in Butylammonium Iodide  
 Abstract    The temperature variations of 'HNMR spin-lattice relaxation times and 'HNMR second moments in «-C 4 H 9 NH 3 I and its N-deuterated analog were studied in a wide range of temper-atures above 77 K. DTA experiments revealed a solid-solid phase transition between room and low temperature phases taking place at 268 K for the former salt and at 267 K for the latter. For rapidly cooled (^ 2 Kmin -1) samples, another phase transition possibly between substable low temperature phases was found at ca. 210 K for the former and ca. 205 K for the latter. The transition entropy observed at 268 K was 33 J K -1 mol -1 . This is much larger than the melting entropy (16 J Kr 1 mol -1), suggesting that butylammonium ions obtain their motional freedom mostly at the phase transition. In the low temperature phase of «-C4H9NH3I, the CH 3 and NH 3 groups perform C 3 reorientation about their respective symmetry axes with the activation energies 10. 4 and 26. 8 kJmol _1 , respectively. The rapidly cooled sample showed two T x components attributable to the stable and substable low temperature phases indicating the coexistence of both phases. In the room temperature phase, the cations rotate rapidly about their long axes and partly conformational disorder of the alkyl chains takes place. The mechanism of the phase transitions is discussed. 
  Reference    Z. Naturforsch. 40a, 347—354 (1985); received December 28 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0347 
 Volume    40 
53Author    N. Hadipour, J. L. RagleRequires cookie*
 Title    Deuterium NQR Spectra: Dipolar Interaction Between Two Quadrupolar Nuclei  
 Abstract    The pure quadrupole spectra of dipolar coupled nuclei in solids contain weak combination and difference bands, usually referred to as DTQR transitions, together with the normal (e.g. allowed) lines. The forbidden lines contain useful information about the relative orientations of the field gradient tensors at the coupled nuclei. If the coupled sites are crystallographically equivalent, the symmetry imposes constraints upon the relative orientations of the tensors, and the spectra contain information which can be used in the assignment of spectra. It is shown how some information may be obtained even in the absence of symmetry constraints. The purpose of this note is the generalization of previous theoretical work, notably by Edmonds and White, to the case of two coupled nuclei of spin / = 1 and with arbitrarily oriented field gradient tensors. The theory is given in a computationally convenient form, and example spectra are given for comparison with recent experimental work in this laboratory. 
  Reference    Z. Naturforsch. 40a, 355—360 (1985); received February 6 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0355 
 Volume    40 
54Author    A. P. Cox, Y. Kawashima, E. Fliege, H. DreizlerRequires cookie*
 Title    Nitrogen-14 Quadrupole Coupling Constants in Propanedinitrile, CH 2 (CN) 2 , by Microwave Spectroscopy  
 Abstract    Nitrogen-14 quadrupole hyperfine structure has been resolved in the microwave spectrum of propanedinitrile, CH 2 (CN) 2 . Measurements between 5 and 30 GHz by Fourier transform and Stark modulation spectroscopy have been analysed. The general matrix elements for nuclear quadrupole interaction in molecules containing two equivalent coupling nuclei have been derived as simple formulae. The quadrupole coupling constants determined for the inertial axis system of CH 2 (CN) 2 are Xaa = ~ 2.368(28) MHz, / bb = 0.318(20) MHz, and Xcf = 2.050(20) MHz. These values are used to establish that the electric field gradient tensor at nitrogen is cylindrically symmetric about the C = N bond with a value of / CN = -4.09(4) MHz, close to values found for other organic cyanides. 
  Reference    Z. Naturforsch. 40a, 361—367 (1985); received January 23 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0361 
 Volume    40 
55Author    H. D. Försterling, H. J. Lamberz, H. SchreiberRequires cookie*
 Title    Kinetics of the Ce 3+ /Br0 2 -Reaction in Sulfuric Acid Medium  
 Abstract    The reaction of Ce 3+ with Br0 2 in sulfuric acid solution (which is the starting step in the inorganic reaction subset of the Belousov-Zhabotinsky-reaction) is followed spectroscopically in a reaction mixture containing Br0 2 at constant concentration. From first order kinetics (Br0 2 in excess) the rate constant for this reaction is evaluated. 
  Reference    Z. Naturforsch. 40a, 368—372 (1985); received January 26 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0368 
 Volume    40 
56Author    T. Mogstad, S. J. Cyvin, B. N. Cyvin, J. Brunvoll, G.Díaz FlemingRequires cookie*
 Title    Molecular Vibrations of Aluminum Trichloride Monomer with Application of the Keating Bendings  
 Abstract    The vibrational spectra and previous normal coordinate analyses of AICI3 are reviewed. The valence force field (VFF), central force field (CFF) and Keating force field (KFF) are tested. KFF is found to be the best one of these approximations with regard to the agreement with an observed isotopic frequency. A final force field is taken from a very recent work. It confirms that KFF is superior to both CFF and KFF. The data of a Coriolis constant, mean amplitudes of vibration and the Bastiansen-Morino shrinkage effect are calculated and discussed. 
  Reference    Z. Naturforsch. 40a, 373—378 (1985); received January 30 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0373 
 Volume    40 
57Author    R. BaltinRequires cookie*
 Title    Exact Green's Function for the Finite Rectangular Potential Well in One Dimension  
 Abstract    For the one-dimensional potential well with finite height ^(^>0 or P6 < 0) the exact Green's function G is calculated by solving the differential equation. The poles of G in the complex energy plane are shown to coincide with the solutions to the Schrödinger eigenvalue equation for this potential. The well-known Green's functions for the special cases of the free particle and of the particle in an infinitely high potential box are recovered. 
  Reference    Z. Naturforsch. 40a, 379—382 (1985); received August 24 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0379 
 Volume    40 
58Author    H. Bürger, P. Schulz, S. CradockRequires cookie*
 Title    Vibrational Spectra and Force Constants of Symmetric Tops, XLVII. Rovibrational Spectra of Three Monoisotopic H 3 GeCl Species in the v 6 Region  
 Abstract    Fourier transform spectra of the monoisotopic species H 3 70 Ge 35 Cl and H 3 74 Ge 37 Cl have been recorded in the v 6 region near 600 cm -1 with a resolution of 0.04 cm" 1 . Rotational analyses based on ~ 700 data for each isotopomer have been performed, and the excited state parameters v®, A 6 . B 6 , AC6, %K-Dk an d h ave been determined. The previously reported analysis of v 6 data of H 3 r4 Ge%Tl has been repeated employing improved ground state constants, and a r.m.s. deviation of ~4x 10~ 3 cm"' has been achieved for the three different isotopic combinations, which show fully consistent excited state parameters. 
  Reference    Z. Naturforsch. 40a, 383—385 (1985); received November 30 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0383 
 Volume    40 
59Author    H. Bürger, A. Rahner, J. KauppinenRequires cookie*
 Title    The Ground State Rotational Constants of H 3 SiD  
 Abstract    The /-dependent rotational constants up to sextic coefficients of H 3 28 SiD were determined by a fit (CT= 3.5 x 10 -4 cirr') of 1505 ground state combination differences formed from transitions of the v 3 , v 5 , and v 6 vibrational fundamentals which were measured with a resolution of 0.005 cm -'. The A-dependent constants A 0 and D° K were obtained from perturbation-allowed transitions observed within v 6 . The ground state constants of the prolate sym-metric top H 3 28 SiD have been determined from 
  Reference    Z. Naturforsch. 40a, 386—388 (1985); received December 24 1984 
  Published    1985 
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 Identifier    ZNA-1985-40a-0386 
 Volume    40 
60Author    Bernd Von MaltzanRequires cookie*
 Title    Eine elektronenspektroskopische Deutung der Konformation dimerer Porphinderivate mit Hilfe des Modells der Wechselwirkung ausgedehnter Dipole  
 Abstract    Derivatives of meso-tetramethylporphine (TMP; la — h), which are analogs of diphenyl-methane and triphenylmethane, and methylene bridged dimers (2a —3i) are examined by electron spectra. The dimers show an intense splitting of the Soretband, which is the result of the conformation of the exciton coupled porphine dimer. The extended dipole model developed by H. Kuhn, H. D. Försterling et al. for aggregates of dye molecules, is used for the interpretation of this interaction. An excellent agreement between the observed and the predicted splitting of the Soret band is found, based on the energetically favoured conformation. Furthermore, this model is examined for literature known examples of porphine dimers. The splitting of the Soretband is also influenced by the solvent, which is explained by changes of the conformation. 
  Reference    Z. Naturforsch. 40a, 389—420 (1985); eingegangen am 21. Januar 1985 
  Published    1985 
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 Identifier    ZNA-1985-40a-0389 
 Volume    40 
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