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1980[X]
121Author    Ivan BotskorRequires cookie*
 Title    Rotational Isomerism and the Orientation of the Total Dipole Moment  
 Abstract    A method for determining the orientation of the total dipole moments of distinct rotamers of the same molecule is discussed. Utilizing solely the experimental dipole moments obtained with microwave spectroscopy (gas phase) and an approximate structure, the orientation of the dipole moment can often be determined without use of bond moment considerations. Experimental data from nine rotamer pairs are analyzed to illustrate the method. 
  Reference    Z. Naturforsch. 35a, 748—756 (1980); received May 8 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0748.pdf 
 Identifier    ZNA-1980-35a-0748 
 Volume    35 
122Author    A. Cingolani, G. Spinolo, M. Sanesi, P. FranzosiniRequires cookie*
 Title    On the Thermal Behaviour of the — W -C20 Potassium Alkanoates  
 Abstract    A DSC study, supplemented by X-ray diffraction measurements, was carried out on potassium soaps from n.tridecanoate to n.eicosanoate in the range between room temperature and the iso-tropic liquid region. The present results are combined with earlier ones for the shorter homologues down to methanoate to draw a rather comprehensive picture of the phase relationships concerned. The significant features shown for a number of transition series by plots AS vs the number of carbon atoms, as well as the dimorphism exhibited by tridecanoate at room temperature are also discussed. 
  Reference    Z. Naturforsch. 35a, 757—765 (1980); received June 2 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0757.pdf 
 Identifier    ZNA-1980-35a-0757 
 Volume    35 
123Author    Wolfgang Brockner, A. Fezä DemirayRequires cookie*
 Title    Ramanspektroskopische Untersuchungen des Systems SeCl4—SbCl5  
 Abstract    Raman spectra of the system SeCt4 -SbCls Raman spectra of the solid and molten SeCU • SbCls addition compound and of some SeCU-SbClö mixtures have been recorded. The structure of the melt can be described by the equilibrium SeCl3 + + SbCl6 _ ^SeCl4 + SbCl5 lying on the side of the complex ions. SeCU decomposes partly into Se2Cl2 and Cl2. Solid mixtures with other stoichiometry contain the 1:1 adduct only and excess SeCU (Se2Cl2) or SbCla, respectively. Such melts are built up by the ionic species SeCl3 + and SbClö -mainly and SeCU (dissolved), Se2Cl2 or SbCls according to stoichiometry. 
  Reference    Z. Naturforsch. 35a, 766—769 (1980); eingegangen am 12. Juni 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0766.pdf 
 Identifier    ZNA-1980-35a-0766 
 Volume    35 
124Author    J. Wiese, R. Schwarz, D. H. SutterRequires cookie*
 Title    Microwavc Spectra of 3-Cyanotliiophene-34 S and 3-Cyanothiophenc-,5 N and Partial restructure  
 Abstract    The rotational spectra of 3-Cyanothiophene-15 N and 3-Cyanothiophene-34 S were analyzed in the frequency range between 10 and 25 GHz. A partial restructure was fitted to the observed rotational constants. The cavity-Fourier-transform microwave spec-trometer with pulsed supersonic nozzle beam gas injection is proposed as a promising tool to investigate the rotational spectra of vibrationally excited moleculs (vvib > 800 cm -1). 
  Reference    Z. Naturforsch. 35a, 770—772 (1980); received June 7 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0770_n.pdf 
 Identifier    ZNA-1980-35a-0770_n 
 Volume    35 
125Author    E. LisickiRequires cookie*
 Title    Shift of the Til 535.0 nm line by hydrogen  
 Abstract    The shift by hydrogen of the 535.0 nm T1 line resulting from photodissociation of thallium iodide was investigated at low densities. A linear variation of the shift with the hydrogen density was found with a shift coefficient of -(0.443 ± 0.012) X 10-20 cm-1 /(molecules cm-3). 
  Reference    Z. Naturforsch. 35a, 773—774 (1980); received March 28 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0773_n.pdf 
 Identifier    ZNA-1980-35a-0773_n 
 Volume    35 
126Author    A. Kawski, M. AlickaRequires cookie*
 Title    Über die Anisotrope Fluoreszenz von donator- substituierten 4-Isocyanat-trans-stilbenen in Lösungsmitteln kleiner Viskosität  
 Abstract    On the Anisotropie Fluorescence of donor substituted 4-isocyanate-trans-stilbene in solvents of low viscosity In solutions of 4-isocyanate-4'-dimethylamino-trans-stil-bene (CDS), 4-isocyanate-4'-methoxy-trans-stilbene (CMS) and 4-isocyanate-3',4'-dimethoxy-trans-stilbene (CDMS) in benzene, chlorobenzene, cyclohexane and cyclohexanol at 293 K, the fluorescence is strongly anisotropic. The emis-sion anisotropies and the lifetimes of these substances were measured. The great emission anisotropy of CDS, CMS and CDMS in solvents of low viscosity is caused by a very short lifetime. 
  Reference    Z. Naturforsch. 35a, 775—776 (1980); eingegangen am 5. Mai 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0775_n.pdf 
 Identifier    ZNA-1980-35a-0775_n 
 Volume    35 
127Author    Angeregten Singulettzustand, I. Gryczyński, D. Gloyna, A. KawskiRequires cookie*
 Title    Einfiuss der Donator-Akzeptor-Wechselwirkung bei Stilbenen auf die Polarität im ersten The Influence of Donor-Acceptor-Interaction in Stilbenes on the Polarity in the First Excited Singlet State  
 Abstract    The electric dipole moments of some substituted stilbenes in the ground (/us) and the first excited singlet state (we) have been determined and discussed in regard of the donor-acceptor-interactions. A linear correlation between the Ham-mett 0p-constants and the values of /Ug, /ue and A/.i = /.ie — Ug for different substituted stilbenes was found. 
  Reference    Z. Naturforsch. 35a, 777—778 (1980); received May 5 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0777_n.pdf 
 Identifier    ZNA-1980-35a-0777_n 
 Volume    35 
128Author    M. ZanderRequires cookie*
 Title    Singlett-Singlett-Energieübertragung im System 5-Acetyl-5H-benzo[b]earbazol/5H-Benzo[b]carbazol  
 Abstract    Singlet-Single Energy Transfer in the System 5-Acetyl-5 II-benzo [b]carbazole/5H-Benzo [6] carbazole 
  Reference    Z. Naturforsch. 35a, 779—780 (1980); eingegangen am 7. Juni 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0779_n.pdf 
 Identifier    ZNA-1980-35a-0779_n 
 Volume    35 
129Author    JohnT. Wasson, John Willis, ChienM. Wai, Alfred KracherRequires cookie*
 Title    Origin of Iron Meteorite Groups IAB and IIICD  
 Abstract    Several low-Ni iron meteorites previously assigned to group IAB are reclassified IIICD on the basis of lower Ge, Ga, W and Ir concentrations and higher As concentrations; the low-Ni extreme of IIICD is now 62 mg/g, that of IAB is 64 mg/g. The resulting fractionation patterns in the two groups are quite similar. It has long been established that, in contrast to the magmatic iron meteorite groups, IAB and IIICD did not form by fractional crystallization of a metallic magma. Other models have been proposed, but all have serious flaws. A new model is proposed involving the formation of each iron in small pools of impact melt on a parent body consisting of material similar to the chondritic inclusions found in some IAB and IIICD irons, but initially unequili-brated. These impact melts ranged in temperatures from ~ 1190 K to ~ 1350 K. The degree of equilibration between melt and unmelted solids ranged from minimal at the lowest temperature to moderate at the highest temperature. The lowest temperature melts were near the cotectic in the Fe-Ni-S system with Ni contents of ~ 12 atom %. Upon cooling, these precipitated metal having ~ 600 mg/g Ni by equilibrium crystallization. The Ni-rich melt resulted from the melting of Ni-rich sulfides and metal in the unequilibrated chondritic parent. Low-Ni irons formed in high temperature melts near the composition of the FeS-Fe eutectic or somewhat more metal rich. We suggest that the decreasing Ge, Ga and refractory abundances with increasing Ni con-centration reflect the trapping of these elements in oxide phases in the unequilibrated chondritic material, and that very little entered the Ni-rich melt parental to the Oktibbeha County iron. The remaining elements tended to have element/Ni ratios in the melts that were more or less independent of temperature. The remarkable correlation between I-Xe age of the chondritic in-clusions and Ni content of the host metal is explained by a detailed evolution of (mega)regolith in which these groups originated. The most Ni-rich melts could only be generated from an un-equilibrated chondrite parent; as the continuing deposition of impact energy produced increas-ingly higher grades of metamorphism, the maximum Ni content of the impact melts (and their subsequently precipitated metal) gradually decreased. 
  Reference    Z. Naturforsch. 35a, 781 (1980); received June 11 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0781.pdf 
 Identifier    ZNA-1980-35a-0781 
 Volume    35 
130Author    Y. Gerstenmaier, D. SchütteRequires cookie*
 Title    Unification of Brueckner Theory and HFB Theory  
 Abstract    A cluster expansion for the expectation value of operators with correlated wave functions is presented. A variational approach to the Brueckner theory with occupation probabilities is gen-eralized and HFB theory incorporated. 
  Reference    Z. Naturforsch. 35a, 796—807 (1980); received March 19 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0796.pdf 
 Identifier    ZNA-1980-35a-0796 
 Volume    35 
131Author    P. ThomaRequires cookie*
 Title    Absolutmessung der kontinuierlichen Strahlung des Heliums im Lichtbogen von X = 109 bis 540 nm  
 Abstract    Measurement of the Helium Continuum Radiation from). = 109 to 540 nm in an Arc Plasma 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 0 at one atmo-sphere with electron temperatures between 25000 K and 26500 K. The electron densities range from 3.0 • 10 16 cm -3 to 4.0 • 10 16 cm -3 and have been determined independently from other plasma parameters by means of line shape measurements. The density of atoms and their kinetic tem-perature have been calculated from the energy balance of the electrons and Dalton's law. Com-parison 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 contri-bution 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 ?i = 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. 
  Reference    Z. Naturforsch. 35a, 808—819 (1980); eingegangen am 8. Mai 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0808.pdf 
 Identifier    ZNA-1980-35a-0808 
 Volume    35 
132Author    Ivan GutmanRequires cookie*
 Title    Proof of Kruszewski's Rule  
 Abstract    A rule for the stability of isomeric polycyclic conjugated compounds, which was recently formulated by Kruszewski [1], is proved. Kruszewski [1] recently examined how the stability of a conjugated compound is changed after addition of a new ring. He concluded that the stability of the newly formed compound depends upon the kind of bond to which the ring is attached and proposed the following rule. (a) If a benzene ring is attached to a conjugated system, then the greater is the ^-electron bond order, the higher is the stability of the obtained product. (b) If a cyclobutadiene ring is attached to a conjugated system, then the situation is reverse: the lower is the bond order, the higher is the stability of the obtained product. Kruszewski arrived at the above rule by compar-ing the results of quantum chemical computations on a large number of examples. In the present paper we shall demonstrate the general validity of this regularity at least on the level of the topological theory of conjugated molecules [2]. In order to formulate Kruszewski's rule in a more precise manner, we need the following nota-tion. Let A be a conjugated system presented by its molecular graph [2] which will also be denoted by A. Then the atom r of the molecule A is represented by a vertex vr of the molecular graph; the bond rs is represented by an edge ers, connecting the vertices vt and vs [2]. We shall assume that it is possible to annelate a new n-membered ring to A either in the position r, A B, B2 
  Reference    Z. Naturforsch. 35a, 820—822 (1980); received June 26 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0820.pdf 
 Identifier    ZNA-1980-35a-0820 
 Volume    35 
133Author    Eizi Morikawa, Masahiro KotaniRequires cookie*
 Title    Exciton Phosphorescence of p-Terphenyl Crystal at 300 K  
 Abstract    Exciton phosphorescence from pure p-terphenyl crystals was observed at 300 K. The 0—0 band of the phosphorescence spectrum was found at 20.4 X 10 3 cm -1 . The vibrational progression of 1.46 x 10 3 cm -1 is present. The maximum exciton lifetime observed was 200 ms. The excitation spectrum of the exciton phosphorescence differs considerably from that observed in glassy solu-tion, but is poorly structured as well. The absorption coefficient near the origin is small. The absence of sensitized delayed fluorescence from doped tetracene suggests that the triplet energy transfer to this guest is not diffusion limited. 
  Reference    Z. Naturforsch. 35a, 823—827 (1980); received March 18 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0823.pdf 
 Identifier    ZNA-1980-35a-0823 
 Volume    35 
134Author    J. Steinwandel, V. E. Joos, M. Hauser, Th DietzRequires cookie*
 Title    Die spezifische Verbreiterung der Fel-Resonanzlinie 3859,91 Ä durch Stöße mit Argonatomen bei hohen Temperaturen  
 Abstract    The specific line-broadening cross section of the Fel-resonance transition at 3859.91 A by collision with argon atoms was measured in the temperature range of 2000 K sS T 3500 K in a shock tube. Driving gas was Helium, shock wave carrier gas and collision partner was Argon. The free iron atoms were produced by the unimolecular decomposition of ironpentacarbonyl in the front of the incident shock wave. The initially produced iron condensate evaporates completely in the reflected shock wave to form free atoms. They are present behind the reflected shock wave in the form of a thermody-namically well defined undersaturated vapour. Thermodynamic quantities of the vapour do not change during the observation time. The line-broadening cross section VL{T) was measured by the method of integral atomic line absorption spectroscopy on the Fel-resonance line at 3859.91 A to (10.05 ± 1-40) x 10~ 15 cm 2 . Temperature variations in CTL are smaller than experimental errors. 
  Reference    Z. Naturforsch. 35a, 828—831 (1980); eingegangen am 10. April 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0828.pdf 
 Identifier    ZNA-1980-35a-0828 
 Volume    35 
135Author    W. Schrepp, H. Dreizler, A. GuarnieriRequires cookie*
 Title    and Stark Switch Techniques  
 Abstract    For the four rotational levels JK~K+ = loi. lio> 2i2 and 2-2i of ethylene oxide all possible four level double resonance experiments for dipole allowed transitions have been performed to in-vestigate collisional effects and to determine the relative change of signal intensity, r] = AI jl, due to high power pump radiation. The TV and TVrelaxation times have been measured for all dipole allowed transitions within these four levels. A combination of the data obtained from both experimental methods allows the determination of rate and bath constants taking into account only first order dipolar transitions. No further restrictions have been used. This approximation is supported by a triple resonance experiment. In addition to the pure gas investigation in the absence of external fields, rotational relaxation has been studied in the presence of a static electric field and in a mixture with hydrogen. 
  Reference    Z. Naturforsch. 35a, 832—840 (1980); received May 22 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0832.pdf 
 Identifier    ZNA-1980-35a-0832 
 Volume    35 
136Author    A.S N Rao, P. Narayana Murty, C.R K Murty, T. Rs, ReddyRequires cookie*
 Title    EPR Study of the Nematic Liquid Crystals: PEBAB and EBRA  
 Abstract    By EPR two nematic liquid crystals PEBAB and EBBA were investigated. The experimental variation of the order parameter with temperature is corroborated with theory. In EBBA a spectrum reminiscent of glassy nature is observed at — 60° C. 
  Reference    Z. Naturforsch. 35a, 841—843 (1980); received May 8 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0841.pdf 
 Identifier    ZNA-1980-35a-0841 
 Volume    35 
137Author    I. Novak, L. Klasinc, J. V. Knop, Th BluhmRequires cookie*
 Title    Photoelectron Spectroscopy of Heterocycles l-(Diazinyl)-2-(Pyridyl)-ethencs (Triazastilbenes)  
 Abstract    The photoelectron (PE) spectra of l-(4-pyrimidyl)-2-(3-pyridyl)-ethene 1, l-(2-pyrimidyl)-2-(3-pyridyl)-ethene 2, l-(4-pyridazinyl)-2-(3-pyridyl)-ethene 3, l-(3-pyridazinyl)-2-(3-pyridyl)-ethene 4 and l-(2-pyrazinyl)-2-(3-pyridyl)-ethene 5 all in their trans conformations have been recorded using Hel radiation. Comparisons with the PE spectra of styrylpvridines, dipyridyl-ethenes and diazabenzenes allowed the assignment of all ionization energies, Ei, corresponding to 7i-and nitrogen lone pair ionizations in the region of Ei < 12 eV. The variations in PE spectra of five isomeric triazastilbenes studied are due to different nitrogen atom positions in the diazinvl ring. 
  Reference    Z. Naturforsch. 35a, 844—847 (1980); received June 21 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0844.pdf 
 Identifier    ZNA-1980-35a-0844 
 Volume    35 
138Author    Magdolna Hargittai, Jon BrunvollRequires cookie*
 Title    On the Internal Motion of Iron Chloride Molecules  
 Abstract    The vibrationally averaged structures of the iron chloride molecules may considerable differ from their equilibrium structure as a consequence of low-frequency large amplitude vibrations. Mean amplitudes of vibration and perpendicular amplitude correction terms have been calcu-lated for FeCl2 and FeCl3. Mean amplitudes of vibration have also been calculated for D2h (equi-librium structure) and Cov (vibrationally averaged structure) symmetry forms of Fe2Cl4 and Fe2Cl6-The applicability of normal coordinate analysis for high temperature systems with large amplitude motion is discussed. 
  Reference    Z. Naturforsch. 35a, 848—851 (1980); received June 2 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0848.pdf 
 Identifier    ZNA-1980-35a-0848 
 Volume    35 
139Author    D. W. Engelfriet, W. L. Groeneveld, G. M. NapRequires cookie*
 Title    ,2,4-Triazole Complexes XII * Magnetic properties of Fe (1, 2, 4-triazole)2 (NCS)2, a quasi two-dimensional S = antiferromagnet with hidden canting  
 Abstract    Fe(trz)2(NCS)2 has been investigated by means of magnetic susceptibility and magnetization measurements on single crystals at temperatures 1.8—300 K, heat capacity measurements at 1.5—90 K and neutron powder diffraction at 1.2 K. The compound orders antiferromagnetically at Tc = 8.46(2) K. The susceptibilities along the orthorhombic axes are strongly anisotropic, the a axis being the preferred direction. The susceptibility data along a and the heat capacity results are in reasonable agreement with the predictions for the quadratic layer, 8 = Ising antiferromagnet, with an intralayer exchange constant J Ik — — 7.2(2) K. Below Tc the mag-netization curve along the a axis reveals a metamagnetic transition at 1.74 kOe. In accordance with the Ising-like properties, a direct transition from the antiferromagnetic to the paramagnetic state is observed along a at 50 kOe. Hidden canting is found to be present. At 1.2 K the compound appears to be monoclinically distorted with a = 88.3° (with respect to Aba2, the space group at 300 K). The magnetic struc-ture consists probably of four sublattices with the magnetic moments lying in the planes 2 = 0 and z — \ (with respect to the distorted cell in Aba2) along directions that are at an angle of 8° with the a axis. Ligand bonding parameters are discussed in terms of the angular overlap model. 
  Reference    Z. Naturforsch. 35a, 852—864 (1980); received June 12 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0852.pdf 
 Identifier    ZNA-1980-35a-0852 
 Volume    35 
140Author    Walter FabianRequires cookie*
 Title    Untersuchungen zur Anwendbarkeit des CNDO/S-CI-Verfahrens für die Berechnung der Anregungsenergien organischer Verbindungen am Beispiel von Phthalsäurederivaten  
 Abstract    The influence of the choice of geometrical parameters and the approximations used to evaluate the two centre coulombic integrals upon excitation energies as calculated by the CNDO/S-or INDO/S-CI method is discussed. 
  Reference    Z. Naturforsch. 35a, 865—868 (1980); eingegangen am 11. Mai 1980 
  Published    1980 
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 TEI-XML for    default:Reihe_A/35/ZNA-1980-35a-0865.pdf 
 Identifier    ZNA-1980-35a-0865 
 Volume    35 
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