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  • 1995-1999  (1)
  • 1980-1984  (2)
  • 1975-1979  (1)
  • Chemistry  (4)
  • 13.10.+q
  • Rare earth elements
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 67 (1998), S. 157-173 
    ISSN: 0020-7608
    Keywords: electron correlations ; charge fluctuations ; correlation strength ; chemical bonds ; first-row homonuclear diatomic molecules ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We investigate, by means of ab initio calculations, the strength of electron correlations within covalent bonds: the first-row homonuclear diatomics serve as test cases. As an appropriate measure of the correlation strength, we introduce the reduction of the mean-square deviations of the electronic charges in localized orbitals forming a bond. A recently developed population analysis in terms of local operators derived from localized molecular orbitals is thereby used. The correlation-strength parameter depends only weakly on dynamical correlations as test calculations demonstrate. Therefore, the full-valence complete active space self-consistent field (CASSCF) approximation is applied in order to study the changes in the correlation strength with changing bond length for different types of bonds. A number of simple rules emerge from this discussion. In addition, we show that charge fluctuations are not only a reliable measure of intrabond correlation effects, but also can be used to monitor intraatomic quasi-degeneracy effects as well as the interdependence within multiple bonds.   © 1998 John Wiley & Sons, Inc. Int J Quant Chem 67: 157-173, 1998
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 480 (1981), S. 199-204 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Effect of Substituents and Anions on the Fluorescence Properties of Mixed-Ligand (Amine-triphenylphosphane) Copper(I) HalidesMixed-ligand complexes analyzing CuHal · PΦ3 · Py—R where Hal = Cl-, Br-, I- and where R are various substituents at the pyridine (Py) exhibit an intense solid state fluorescence depending on substituent and anion when excited with uv radiation (365 nm). It will be shown that there is a relation between fluorescence and mesomeric and inductive properties of substituents and anions.
    Notes: Gemischtligandige Komplexe der Zusammensetzung CuHal · PΦ3 · Py—R mit Hal = Cl-, Br-, I- und R = verschiedenen Substituenten am Pyridin (Py) weisen bei UV-Bestrahlung (365 nm) im festen Zustand eine intensive Fluoreszenz auf. Es soll gezeigt werden, daß ein Zusammenhang der Fluoreszenz mit den mesomeren und induktiven Eigenschaften von Substituenten und Anionen besteht.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 480 (1981), S. 193-198 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Results on Fluorescence Properties of Sesqui-, Bis- and Tris(triphenylphosphane) Copper(I) HalidesThe solid state fluorescence and excitation spectra of sequi-, bis- and tris(triphenylphosphane) copper(I) halides  -  (CuHal)2(PΦ3)3; CuHal(PΦ3)2; CuHal(PΦ3)3  -  at 300 K and 77 K are now completely registrated. The fluorescence is almost independent of the halide anion, whereas excitation is influenced. Furthermore, solvate molecules do not change the fluorescence. Dimeric sesqui compounds show a red shift of emission when cooled, but monomeric bis and tris complexes undergo a blue shift of emission by cooLing.
    Notes: Die Fluoreszenz- und Anregungsspektren der Sesqui-, Bis- und Tris(triphenylphosphan)kupfer(I)-Halogenide  -  (CuHal)2(PΦ3)3; CuHal(PΦ3)2; CuHal(PΦ3)3  -  im festen Zustand bei 300 K und 77 K liegen jetzt vollständig vor. Die Fluoreszenz ist nahezu unabhängig vom Halogenidion, wohingegen die Anregung beeinflußt wird. Weiterhin führen Solvatmoleküle zu keiner Fluoreszenzänderung. Beim Abkühlen von dimeren Sesqui-Verbindungen wird deren Emission nach rot verschoben, während die Emissionen monomerer Bis- und Tris-Verbindungen beim Abkühlen einer Blauverschiebung unterliegen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 442 (1978), S. 221-224 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: About the Fluorescence Thermochromism of Acetonitrile Copper Iodide with Dibenzo-18-Crown-6Copper iodide reacts in actonitrile solution with dibenzo-18-crown-6 to form a compound,(CuJ)4(CH3CN)4(db-18-c-6), which fluoresces yellow at 298K, but pink at 77 K. It decomposes at 55.3°C. (5 Torr) by lost of acetonitrile and a heterogeneous mixture of copper iodide and polyether results. In absence of dibenzo-18-crown-6, copper iodide forms with acetonitrile a heterogeneous mixture of copper iodide and polyether results. In absence of dibenzo-18-crown-6, copper iodide forms with acetonitrile a solvate CuJ. CH3CN. It also shows fluorescence thermochromism (yellow at 298 K, but green at 77 k) but decomposes at 0°C and 760 Torr.The luminescences pectra of the macrocyclic polyether complex at 298 K is redshifted. This probably results from intersection between the crown and the acetonitrile copper iodide.
    Notes: Kupferjodid bildet in Acetonitril mit Dibenzo-18-Krone-6 eine Verbindung der Zusammensetzung (CuJ)4(CH3CN)4(db-18-c-6), die bei Raumtemperatur gelb, bei 77K rosa fluoresziert. Sie zersetzt sich bei 55,3°C (5 Torr) unter Verlust von Acetonitril zu einem heterogenen Gemenge aus Kronenäther Kupferjodid.In Abwesenheit von Kronenäther bildet Kupferjodid in Acetonitril ein Solvat CuJ · CH3CN. Es ist ebenfalls fluoreszenzthermochrom (gelb bei 298 K, grün bei 77 K) und zersetzt sich allerdings schon bei 0°C( 760 Torr). Das Lumineszenzspektrum des makrocyclischen Polyätherkomplexes ist bei 298 K rotverschoben, was wahrscheinlich auf die Wechselwirkung des Kronenäthers mit dem Acetonitrilo-Kupferjodid zurückzuführen ist.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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