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  • 1
    Electronic Resource
    Electronic Resource
    Quantum creation of the universe with a minimum scalar-field energy (1996)
    Springer
    JETP letters 64 (1996), S. 329-333 
    Details
    ISSN: 1090-6487
    Keywords: 03.65.Bz
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The quantum creation of a closed Friedmann universe is studied on the basis of a Wheeler-DeWitt equation with two arguments — a scale factor and a scalar-field potential. In the quasiclassical approximation the wave function of the universe (WF) starts to evolve at a zero scalar field. A near-Planckian energy density of the field arises as a result of tunneling through a potential barrier. In our opinion, this variant of the scenario most closely resembles creation ex nihilo. The only parameter controlling quantum evolution is the mass of a quantum of the scalar field. In the paper by Khalatnikov and Schiller [JETP Lett. 57,1 (1993)], tunneling through the classically inaccessible region of the superpotential U(a,φ) is calculated by the instanton method. However, this method requires that the potential U(a,φ) satisfy special conditions in the space (a,φ). For this reason, in the present paper the tunneling calculation is performed by the method of characteristics for the quasiclassical approximation of the Wheeler-DeWitt equation under the barrier. The WKB theory, which has been well-developed for one-dimensional problems, is employed along each characteristic. It is shown that the corresponding turning points are also points where U(a, φ)=0. The total barrier penetrability is obtained by averaging over a bundle of characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567198
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  • 2
    Electronic Resource
    Electronic Resource
    The nature of active centers in cyclotrimerization of isocyanates catalyzed by the tertiary amine—α-oxide—proton donor system 1. The role of the proton donor (1996)
    Springer
    Russian chemical bulletin 45 (1996), S. 1312-1315 
    Details
    ISSN: 1573-9171
    Keywords: catalytic systems ; cyclotrimerization ; isocyanates ; hydrogen bonds ; molecular complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The rate of cyclotrimerization of phenyl isocyanate in chlorobenzene at 120 °C in the presence of the tertiary amine-α-oxide-proton donor (PD) ternary catalytic system has been studied using a dual calorimeter and a series of phenols with various acidities as the PD. In the presence of weakly acidic phenols, complexes of quaternary ammonium type bases are formed in the ternary catalytic systems. Acidic phenols afford salt complexes with the transfer or a proton from phenol to the tertiary amine in a quantitative yield, while the α-oxide present remains unaffected. The structures of the complexes were studied by IR and by IR and1H NMR spectroscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01434203
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  • 3
    Electronic Resource
    Electronic Resource
    The preparation and X-ray structural study of complexes that catalyze isocyanate cyclotrimerization (1993)
    Springer
    Russian chemical bulletin 42 (1993), S. 81-87 
    Details
    ISSN: 1573-9171
    Keywords: isocyanate polycyclotrimerization catalysts ; X-ray analysis ; molecular complexes ; strong H-bonds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A 1∶1-complex of trinitrophenol with benzyldimethylamine (1) and a 1∶1∶1-complex, the product of the interaction of benzyldimethylamine, glycidyl phenyl ether, and phenol (2), have been synthesized and characterized by means of X-ray analysis. Complex1 is a precursor for the catalysts of selective isocyanate cyclotrimerization, while complex2 is one of those catalysts. In the crystal structure complex1 forms H-bonded cationic-anionic aggregates with proton transfer from phenol to the N-atom of the tertiary amine. Complex2 crystallizes as a monohydrate (2a) with a strong H-bond between the quaternary ammonium and phenolic components, and exists in crystals in the form of globular H-bonded dimeric hydrates. Possible pathways of dissociation of complex2a are discussed. The data obtained may be used as a basis for further interpretation of the regularities of cyclotrimerization of isocyanates catalyzed by complexes of this type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00699980
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