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1978[X]
21Author    D. F. Düchs, S. Rehker, J. OxeniusRequires cookie*
 Title    Non-LTE Line Transfer with Diffusion of Excited Atoms II  
 Abstract    Non-LTE radiative transfer in a spectral line due to two-level atoms is studied taking the diffusion of excited atoms into account. Numerical results are presented for the case of a sta-tionary, plane parallel plasma of constant total density and temperature without external radia-tion and without exchange of matter with the surroundings, assuming pure Doppler broadening of the spectral line. 
  Reference    Z. Naturforsch. 33a, 124 (1978); received December 5 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0124.pdf 
 Identifier    ZNA-1978-33a-0124 
 Volume    33 
22Author    G. AmorettiRequires cookie*
 Title    Effect of Polar States on Superexchange Interaction. Application to Some Dimeric Copper (II) Complexes and to CuCl2 * 2 H20 Linear Chain  
 Abstract    The effect of polar states on the superexchange interaction between two identical spin 1/2 magnetic ions is examined. The one-body potential contributions to the effective exchange constant Jeff are written in terms of the splitting 2AQ between the bonding and antibonding single particle lower-states of the dimeric complex. Moreover, the energies of the basis triplet and singlet states are obtained in an approximated form as functions of Ao and of two-body molecular integrals. The resulting Jeff> that is the splitting between the lowest singlet and the triplet, differs from that of the pure Heitler-London treatment owing to the ionic contributions to the singlet wavefunction. The theory is applied to some dimeric copper (II) complexes and to CuCl2 • 2H2O linear chain. It is shown that the polar state corrections are generally small, but that they may become important in the case of copper chlorine, where the various con-tributions to the Heitler-London exchange constant tend to balance each other to give a very small value. Moreover, antiferromagnetic coupling for CuCl2 • 2H2O is accounted for on the basis of a cx-ground state for the single unit, rather than a n one. The conditions to fit the ex-perimental value of Jeff are also discussed. 
  Reference    Z. Naturforsch. 33a, 130—140 (1978); received November 7 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0130.pdf 
 Identifier    ZNA-1978-33a-0130 
 Volume    33 
23Author    N. P. Ferreira, P. A. BügerRequires cookie*
 Title    Redeposition of Sputtered Material in a Glow-Discharge Lamp Measured by Means of an Ion Microprobe Mass Analyser  
 Abstract    The redeposition of sputtered material on the target in a Grimm-type glow-discharge lamp was studied by means of an ion microprobe mass analyser (IMMA) using 16 02 + ions as bombard-ing species. The target was an aluminium disc with a cylindrical copper insertion, one mm in diameter. The lamp was operated at currents of 50 mA and 100 mA and a voltage of 1200 V. It is estimated that 17% of the copper atoms sputtered are redeposited and may be resputtered. 
  Reference    Z. Naturforsch. 33a, 141—144 (1978); received September 16 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0141.pdf 
 Identifier    ZNA-1978-33a-0141 
 Volume    33 
24Author    Anil Kumar, John Sheridan, OttoL. StiefvaterRequires cookie*
 Title    The Microwave Spectrum of Oxazole I. The Complete Structure by DRM Microwave Spectroscopy  
 Abstract    Double resonance modulation (DRM) microwave spectroscopy has been used to determine the complete substitution structure of oxazole. Isotopic species spectra associated with 13 C, 15 N and 18 0 were studied in their natural abundances, while the mono-deuterated species were examined in a mixture of slightly enriched forms. With uncertainties below 0.002 A and 0.1° for distances and angles, respectively, the structure parameters of oxazole are as follows: 0(1)-C(2) = 1.3574 Ä C(5)0(1)C(2) = 103.9i° C(2)-N(3) = 1.2915A 0(1)C(2)N(3) = 114.99° N(3)-C(4) = 1.3954 Ä C(2)N(3)C(4) = 103.92° C(4)-C(5) = 1.352s Ä N(3)C(4)C(5) = 109.04° C(5)-0(l) = 1.3696A C(4)C(5)0(1) = IO8.I4 0 C(2)-H(2) = 1.0750 A 0(1)C(2)H(2) = 117.09° C(4)-H(4) = 1.075i A N(3)C(4)H(4) = 121.89° C(5)-H(5) = 1.0732 A 0(1)C(5)H(5) = 116.8e° The geometry of oxazole is compared with that of isoxazole and with the structures of the closely related compounds furan and 1,3,4-oxadiazole. 
  Reference    Z. Naturforsch. 33a, 145—152 (1978); received December 8 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0145.pdf 
 Identifier    ZNA-1978-33a-0145 
 Volume    33 
25Author    OttoL. StiefvaterRequires cookie*
 Title    The Microwave Spectrum of Oxazole The DRM-Spectrum of the 15 N-Species in its Natural Abundance  
 Abstract    In view of a discrepancy between the rotational constants of the 15 N-species of oxazole reported in an earlier study on a pure 15 N-sample and those found in a recent study on a sample containing the 15 N-species only in its natural abundance, the experimental results of the latter study are reported in detail, and they are compared with predictions based on the results of the earlier work. 
  Reference    Z. Naturforsch. 33a, 153—155 (1978); received December 8 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0153.pdf 
 Identifier    ZNA-1978-33a-0153 
 Volume    33 
26Author    Harold Jones, Michio Takami, John SheridanRequires cookie*
 Title    Microwave Spectrum of Chloroacetylene in Ground and Excited Vibrational States  
 Abstract    The microwave spectrum of chloroacetylene in the ground and excited states has been in-vestigated in the frequency range 15 to 306 GHz. Ground state rotational and nuclear quadrupole coupling constants for twelve isotopic species of chloroacetylene and accurate distortion con-stants were determined for two of these. The data allowed the restructure of chloroacetylene to be reconsidered and the internal consistency of this method of structure determination to be checked. Rotational spectra in five vibrationally excited states, with energy up to 700 cm -1 were observed for four different isotopic species and spectroscopic constants for these states were derived. 
  Reference    Z. Naturforsch. 33a, 156—163 (1978); received December 15 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0156.pdf 
 Identifier    ZNA-1978-33a-0156 
 Volume    33 
27Author    EdvardA. HemmingsenRequires cookie*
 Title    Effects of Surfactants and Electrolytes on the Nucleation of Bubbles in Gas-Supersaturated Solutions  
 Abstract    Various solutions of surfactants and electrolytes were equilibrated with argon at gas pressures up to 202 atm and then decompressed to atmospheric pressure while observed visually or cine-micrographically for occurrence of bubbles. In water, the threshold gas supersaturations for spontaneous nucleation of bubbles at the glass-water interface and in the bulk liquid were 135 atm and 155 atm, respectively. Among the surfactants, only those of molecular weight less than about 330 daltons significantly decreased the cavitation thresholds; those of higher weights had no effect. The electrolytes either had small to moderate or no effect on the threshold, although the dissolved gas concentrations resulting from the solubility changes were greatly decreased. The data indicate that changes in the structure of the solvent water may affect the nucleation process. 
  Reference    Z. Naturforsch. 33a, 164—171 (1978); received October 25 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0164.pdf 
 Identifier    ZNA-1978-33a-0164 
 Volume    33 
28Author    L. Åsbrink, C. Fridh, E. LindholmRequires cookie*
 Title    Ionization, Excitation and Electron Affinity of Naphthalene, Studied with HAM/3  
 Abstract    The electronic structure of naphthalene is calculated using the new semiempirical method HAM/3. The calculated photoelectron spectrum is in reasonable agreement with the measured spectrum. The excitation energies are obtained directly in HAM as the difference of the energies of the unoccupied and the occupied orbitals, and the calculated UV spectrum is in good agreement with experiment. The electron affinities are also obtained directly and are also in agreement with recent measurements. The absorption spectrum of the naphthalene anion is in reasonable agreement with experiment also regarding intensities. All calculations did not require more 76 seconds computer time although no advantage was taken of the symmetry of the molecule. 
  Reference    Z. Naturforsch. 33a, 172—180 (1978); received November 23 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0172.pdf 
 Identifier    ZNA-1978-33a-0172 
 Volume    33 
29Author    Ernst LiebermannRequires cookie*
 Title    Voraussage der Temperaturabhängigkeit des Zusatzvolumens einfacher binärer nichtassoziierter Mischungen aus Reinstoffdaten  
 Abstract    An equation relating the temperature dependence of the excess volume F E of simple binary liquid nonassociated mixtures to the molar volumes, the isobaric expansivities and the isothermal compressibilities of the pure solvents is proposed. The treatment is based on averaging over the macroscopic properties of the unmixed components on the grounds of classical thermodynamics. Predictions are made without using any empirical parameter. 
  Reference    Z. Naturforsch. 33a, 181 (1978); eingegangen am 8. Oktober 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0181.pdf 
 Identifier    ZNA-1978-33a-0181 
 Volume    33 
30Author    G. Heppke, E.-J RichterRequires cookie*
 Title    Induktion smektischer Phasen in binären Mischungen nematischer Flüssigkristalle  
 Abstract    Induction Binary mixtures of 4-n-alkyl-and 4-w-alkyloxy-4'-cyanobiphenyls with homologous 4,4'-di-«-alkyloxy-azoxybenzenes exhibit the induction of a smectic phase. From some of the phase dia-gram it can be concluded that the induced smectic phases (ISP) are of the Sa type, and this is probably true for all mixtures studied. The thermal stability of the induced smectic phases can not be correlated with the clearing temperatures of the single components, but a dependence on their ability to form smectic phases is very likely. It is postulated that mixtures of terminal polar and terminal non polar nematic liquid crystals are generally able to exhibit the induction of smectic phases. 
  Reference    Z. Naturforsch. 33a, 185—189 (1978); received December 24 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0185.pdf 
 Identifier    ZNA-1978-33a-0185 
 Volume    33 
31Author    Roger Blachnik, Paul-G GuniaRequires cookie*
 Title    Enthalpien von Kupfer-und Silberchalkogeniden  
 Abstract    The enthalpy contents of Cu2Se, CuaTe, Ag2Se and Ag2Te at temperatures between 350 K to 50 K above the melting points were measured in an isoperibolic drop-calorimeter. Thermo-dynamic data of the compounds were derived from these measurements. An analysis of the data leads to the conclusion that a high degree of order is retained in the melts of these compounds, and that the bond character of these melts is partially ionic. An unusual decrease of Cp with increasing temperature immidiately after the transition temperatures could be confirmed. 
  Reference    Z. Naturforsch. 33a, 190 (1978); eingegangen am 25. November 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0190.pdf 
 Identifier    ZNA-1978-33a-0190 
 Volume    33 
32Author    H. Dreizler, W. SchreppRequires cookie*
 Title    Investigation of Collision Induced Transitions in the Microwave Range: Ethylene Oxide and Carbonylsulfide  
 Abstract    Collisional energy transfer between rotational levels of ethylene oxide C2H4O, its deuterated species C2D4O and carbonyl sulfide OCS, has been investigated by means of microwave-micro-wave four-level double resonance. The results are in agreement with collisional selection rules which can be predicted in the weak collision limit. Collisionally induced transitions up to AJ = 4 have been detected for C2D4O. 
  Reference    Z. Naturforsch. 33a, 197—203 (1978); received November 5 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0197.pdf 
 Identifier    ZNA-1978-33a-0197 
 Volume    33 
33Author    G. K. Pandey, H. DreizlerRequires cookie*
 Title    Rotation-Torsion-Vibration Interaction in Acetyl Cyanide: Normal and 15 N Isotopic Species  
 Abstract    The rotation — torsion — vibration interaction in the normal and 15 N isotopic species of Acetyl Cyanide is studied in the rotational spectrum of ground, first excited state of methyl torsion and first excited state of CCN in plane bending vibration. With respect to a previous -work [1] a more detailed check of a model with five degrees of freedom, comprising three for the overall rotation and two for the two lowest vibrations was possible. Potential parameters were fitted simultaneously to the splittings of the rotational transitions in the ground, excited torsional and excited vibrational states for the normal and 15 N isotopic species of the molecule. The coefficients F3 and of the Fourier expansion of the hindering potential for the torsion and two interaction constants V3c' and F3/' for the torsion and in plane CCN bending vibration were determined, apart from the harmonic force constant k<zq for the vibration, which is obtained from the measured infrared data of the normal species. Using these results, the (E-A) splittings of the rotational transitions could be nicely reproduced but not the absolute frequencies of the rotational transitions. 
  Reference    Z. Naturforsch. 33a, 204—213 (1978); received December 7 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0204.pdf 
 Identifier    ZNA-1978-33a-0204 
 Volume    33 
34Author    Ivan GutmanRequires cookie*
 Title    Electronic Properties of Möbius Systems  
 Abstract    The main 7r-electron properties (energy level distribution, total electron energy, charge dis-tribution) of Möbius systems are analysed. A number of results, known previously for Hückel systems is generalized and/or modified for Möbius systems. The main conclusions of the work are summarized in Rules 1 — 7. 
  Reference    Z. Naturforsch. 33a, 214—216 (1978); received October 24 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0214.pdf 
 Identifier    ZNA-1978-33a-0214 
 Volume    33 
35Author    H. Sterk, H. KoppRequires cookie*
 Title    *H Spin-Gitter-Relaxationszeitmessungen an Alkoholen  
 Abstract    l H Spin-Lattice Relaxationtime Measurements on Alcohols *H spin-lattice relaxationtimes Ti have been measured on alcohols, ethers, acetylacetone and cyclohexandione-1,3, solved in CCI4 and pure. The relaxationtime T\ increases characteristically with decreasing chain length, molecular size and viscosity, as well as with the distance from the OH-group and CCI4 dilution. Segmental motions and the breaking of hydrogen bondings are determined as the reason of this behaviour. Deuteron substitution and T\ measurements at different temperatures show that the dipol-dipol interaction is the predominant mechanism of relaxation. 
  Reference    Z. Naturforsch. 33a, 217—221 (1978); eingegangen am 22. Dezember 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0217.pdf 
 Identifier    ZNA-1978-33a-0217 
 Volume    33 
36Author    Jon Brunvoll, Istvan Hargittai, Ragnhild SeipRequires cookie*
 Title    The Molecular Geometry of Trichloromethyl Sulphonyl Chloride as Studied by Electron Diffraction. Estimation of the Barrier to Internal Rotation  
 Abstract    The molecular geometry of trichloromethyl sulphonyl chloride has been determined by electron diffraction. The sulphur bond configuration [rg(S=0) 1.421 ±0.003 A, rg(S-Cl) 2.021 ±0.005 A, rg(S —C) 1.87±0..5±0.9° and zO = S —Cl 109.2 ±0.6°] is consistent with the characteristic structural variations observed in the sulphone series. The barrier to internal rotation around the S—C bond was estimated to be between 3.5 and 6 kcal mol -1 by means of various procedures and assumptions. 
  Reference    Z. Naturforsch. 33a, 222—224 (1978); received December 5 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0222.pdf 
 Identifier    ZNA-1978-33a-0222 
 Volume    33 
37Author    W. E. KöhlerRequires cookie*
 Title    Top Molecules in Perpendicular Electric and Magnetic Fields  
 Abstract    A kinetic theory treatment of the influence of perpen-dicular magnetic and electric fields on the viscosity is given for a polar gas of symmetric top molecules. Expressions for the 9 independent viscosity coefficients are derived. In particular, the electric field influence on the transverse viscomagnetic pressure difference is studied. 
  Reference    Z. Naturforsch. 33a, 225 (1978); received November 14 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0225_n.pdf 
 Identifier    ZNA-1978-33a-0225_n 
 Volume    33 
38Author    R. ClausRequires cookie*
 Title    Do Free Carriers Influence Polariton Scattering Intensities in GaAs?  
 Abstract    An influence of free carriers in GaAs on polariton scat-tering intensities is shown to take place due to two mechanismus: a) The altered LO-phonon frequency changes the electrooptic coefficient and b) the macroscopic electric field becomes changed. Both quantities influence the scattering intensities. 
  Reference    Z. Naturforsch. 33a, 231 (1978); received November 25 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0231_n.pdf 
 Identifier    ZNA-1978-33a-0231_n 
 Volume    33 
39Author    OttoS. Wolfbeis, E. LippertRequires cookie*
 Title      
 Abstract    The fluorescence spectra of the title compound have been measured in ethanol and in aqueous solutions of different pH. In ethanol the neutral molecule's fluorescence (at 360 nm) is observed, whereas in aqueous solutions emission occurs from the anion (at 428 nm) and from a "tautomeric" species (at 460 nm), but not from the neutral molecule. An aqueous solution at pH 3, which contains about 30% of ethanol gives a broad fluorescence band ranging from the near uv to the orange region of the spectrum. Contrarily, 7-methoxylepidone has no fluorescence maximum in the visible part of the spectrum. 
  Reference    Z. Naturforsch. 33a, 238—239 (1978); received November 23 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0238_n.pdf 
 Identifier    ZNA-1978-33a-0238_n 
 Volume    33 
40Author    V. Jayathirtha, KrishnanRequires cookie*
 Title     
 Abstract    Fluoranil forms weak 1:1 molecular complexes with both benzene substituted and nonbenzenoid macrocyclic ethers. 19 FMR shifts have been used for the evaluation of associa-tion constants. The infrared and 1 HMR data of the com-plexes reveal relative orientations of the molecules in the complexes. 
  Reference    Z. Naturforsch. 33a, 243—244 (1978); received November 4 1977 
  Published    1978 
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 TEI-XML for    default:Reihe_A/33/ZNA-1978-33a-0243_n.pdf 
 Identifier    ZNA-1978-33a-0243_n 
 Volume    33 
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