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  • 1
    Electronic Resource
    Electronic Resource
    Self-consistent truncation of the BBGKY hierarchy on the two-body level (1992)
    Springer
    The European physical journal 342 (1992), S. 161-167 
    Details
    ISSN: 1434-601X
    Keywords: 24.10.Cn ; 25.70.−z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present a coupled set of equations for the one-body density matrix and the two-body correlation function consistent with trace relations and conservation laws which provide an extension of correlation dynamics on the two-body level. The additional interaction terms are discussed in the context of time-dependent G-matrix theory and NQCD and studied numerically by one-dimensional calculations for colliding finite fermion systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01288464
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  • 2
    Electronic Resource
    Electronic Resource
    Correlation dynamics of finite fermion systems (1990)
    Springer
    The European physical journal 337 (1990), S. 175-183 
    Details
    ISSN: 1434-601X
    Keywords: 24.10.Cn ; 25.70.−z
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The dynamical description of strongly interacting finite Fermi systems is based on coupled equations of motion for the one-body density matrixρ(11′) and the two-body correlation functionc 2(12, 1′2′) as obtained from the density-matrix hierarchy. The truncation schemes considered exceed the conventional Brueckner-Hartree-Fock scheme and also apply for nonstationary problems. In the limit of slow processes in time the equation of motion for the two-body correlation functionc 2 can be integrated in time and closed expressions can be given for the dynamical evolution ofρ(11′). When performing a Wigner transformation and adopting semiclassical limits this gives a transport equation of the Uehling-Uhlenbeck type for the one-body phase-space distributionf(x,p;t). Furthermore, in the small amplitude limit, we obtain a set of coupled equations for particle-hole (p-h),2p-2p, 2h-2h, 2p-2h, 1p-3h, 1h-3p amplitudes beyond the level of second RPA which provide a genuine basis for the description of giant resonances and their damping width.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01294289
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  • 3
    Electronic Resource
    Electronic Resource
    Mößbauer- und Neutronenbeugungs-Messungen an Li6FeCl8 (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 901-904 
    Details
    ISSN: 0044-2313
    Keywords: Iron chlorides, lithium ; Mößbauer spectra ; neutron diffraction ; Suzuki type ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mößbauer and Neutron Diffraction Studies on Li6FeCl8On Suzuki-Type Li6FeCl8 Mößbauer spectra and neutron powder diffraction data are presented. The Suzuki-type structure (space group Fm3m, Z = 4, 1 031.11(1) pm) was supported refining by the Rietveld method (program PROFIL) to a final R1 = 6.8%. The Mößbauer spectra confirm the ideal octahedral coordination of the Fe2+ ions (no quadrupole splitting). The isomer shift of 1.097(1) mm s-1 at 295 K resembles those of other ferrous chlorides. At temperatures above the phase transition to deficient NaCl-type solid solution the half-width of the Mößbauer signal strongly increases.
    Notes: Die Mößbauer-Spektren und Neutronenpulver-Strukturdaten der Suzukiphase Li6FeCl8 werden mitgeteilt. Die Struktur (Raumgruppe Fm3m, Z = 4, a = 1 031,11(1) pm) konnte mit Hilfe des Rietveld-Verfahrens (Programm PROFIL) bis zu einem R-Wert R1 = 6,8% verfeinert werden. Die Mößbauer-Spektren ergeben eine exakt oktaedrische Umgebung von Fe2+ (keine Quadrupol-Aufspaltung). Die Isomerieverschiebung (1,097(1) mm s-1 bei 295 K) entspricht der anderer Eisen(II)chloride. Bei Temperaturen oberhalb der Phasenumwandlung zum defizienten NaCl-Typ-Mischkristall nimmt die Halbwertsbreite des Mößbauer-Signals zu.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190517
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  • 4
    Electronic Resource
    Electronic Resource
    Neue Halogenozinkate(II) M2IZnX4 (MI = Li, Na; X = Cl, Br) mit OlivinstrukturProfessor Heinrich Nöth zum 65. Geburtstage gewidmet (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 993-998 
    Details
    ISSN: 0044-2313
    Keywords: Bromozincates ; zinc ; olivine-type halides ; neutron diffraction ; fast ionic conductivity ; Raman spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Halogenozincates M2IZnX4 (MI = Li, Na; X = Cl, Br) of Olivine TypeThe hitherto unknown tetrabromozincates Li2ZnBr4 and Na2ZnBr4 have been prepared. Quaternary halides Li2Zn(Cl, Br)4 and Li2Zn(Br, I)4 have been not obtained due to decomposition to mixtures of LiCl and ZnBr2, and LiBr and ZnI2. The crystal structures of the olivine-type bromides and of the high-temperature polymorph of Li2ZnCl4 have been determined by neutron powder diffraction using the Rietveld method (space group Pnma, Z = 4, a = 1 360.41(4), b = 788.47(2), c = 647.07(2) pm, RI = 9.07% (Li2ZnBr4), a = 1 446.32(5), b = 853.02(3), c = 676.61(2) pm, RI = 9.29% (Na2ZnBr4), a = 1 277.60(3), b = 741.76(2), c = 611.10(1) pm, RI = 7.63% (Li2ZnCl4)). The Raman spectra as well as the results of thermal analyses (DSC) and conductivity measurements (impedance spectroscopy) are presented and discussed. Contrary to Li2ZnCl4, Li2ZnBr4 and Na2ZnBr4 do not undergo any phase transition between 20°C and their melting points.
    Notes: Die Darstellung der bisher nicht bekannten Tetrabromozinkate Li2ZnBr4 und Na2ZnBr4 wird beschrieben. Quaternäre Halogenide des Typs Li2Zn(Cl, Br)4 bzw. Li2Zn(Br, I)4 konnten nicht erhalten werden. Es erfolgt Entmischung zu LiCl und ZnBr2 bzw. LiBr und ZnI2. Die Kristallstrukturen der im Olivintyp kristallisierenden Bromide und der Hochtemperaturform von Li2ZnCl4 wurden auf der Basis von Neutronenpulver-Messungen nach der Rietveld-Methode bestimmt (Raumgruppe Pnma, Z = 4, a = 1 360,41(4), b = 788,47(2), c = 647,07(2) pm, RI = 9,07% (Li2ZnBr4), a = 1 446,32(5), b = 853,02(3), c = 676,61(2) pm, RI = 9,29% (Na2ZnBr4), a = 1 277,60(3), b = 741,76(2), c = 611,10(1) pm, RI = 7,63% (Li2ZnCl4)). Raman-Spektren sowie das Ergebnis thermoanalytischer Untersuchungen (DSC) und Leitfähigkeitsmessungen (Impedanz-Spektroskopie) werden mitgeteilt. Li2ZnBr4 und Na2ZnBr4 zeigen im Gegensatz zu Li2ZnCl4 zwischen 20°C und dem Schmelzpunkt keine Phasenumwandlung.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190606
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  • 5
    Electronic Resource
    Electronic Resource
    Synthese und Strukturbestimmung von (i-Pr)2NB(t-BuP)3 und (i-Pr)2NB(t-BuP)4Professor Ernst-Otto Fischer zum 75. Geburtstage gewidmet (1994)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 8-15 
    Details
    ISSN: 0044-2313
    Keywords: P3B and P4B ring systems ; NMR data ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Structure Analysis of (i-Pr)2NB(t-BuP)3 and (i-Pr)2NB(t-BuP)4The diphosphide K(t-Bu)P-(t-BuP)2-P(t-Bu)K obtained by the cleavage reaction of the 3-membered ring system (i-Pr)2BN(t-BuP)2 with potassium reacts with t-BuPCl2 at -78°C under ring expansion to form the P3B ring system (i-Pr)2NB(t-BuP)3 - 1,2,3-tri-t-butyl-tri-phospha-4-diisopropyl-aminoboretane (1). - The 5-membered P4B ring system (i-Pr)2NB(t-BuP)4 - 1,2,3,4-tetra-t-butyl-tetraphospha-5-diisopropylaminoborolidine, (2) - is formed from K(t-Bu)P—(t-BuP)2—P(t-Bu)K and (i-Pr)2NBCl2 analogous to the above reaction. 1 and 2 could be obtained in a pure form and characterized NMR spectroscopically and by X-ray structure analysis. 1 shows at 200 K two conformation isomers; for 2 31P-10,11B-isotopic shifts could be identified.
    Notes: Das bei der Spaltung des Dreiringes (i-Pr)2BN(t-BuP)2 mit Kalium gebildete Diphosphid K(t-Bu)P—BN(i-Pr)2—P(t-Bu)K reagiert bei -78°C mit t-BuPCl2 unter Ringerweiterung zu (i-Pr)2NB(t-BuP)3-1,2,3-Tri-t-butyl-triphospha-diisopropyl-aminoboretan, (1) - mit einem P3B-Ringgerüst. In analoger Weise entsteht bei der Reaktion zwischen K(t-Bu)P—(t-BuP) - (t-BuP)2—P(t-Bu)K und (i-Pr)2NBCl2 das P4B-Ringsystem (i-Pr)2NB(t-BuP)4 - 1,2,3,4-Tetra-t-butyl-tetraphospha-5-diiso-propylaminoborolidin, (2) -, 1 und 2 konnten in reiner Form isoliert, NMR-spektroskopisch und durch Röntgenstrukturanalysen charakterisiert werden. 1 zeigt bei 200 K zwei Konformationsisomere; bei 2 konnten 31P-10,11B-Isotopieverschiebungen nachgewiesen werden.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19946200104
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