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  • 1
    Electronic Resource
    Electronic Resource
    Calculation of crystal and molecular structures of hexachlorobenzene C6Cl6 (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 10940-10947 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Crystal and molecular structures of hexachlorobenzene C6Cl6 were investigated by molecular-packing analysis with a computed dynamical model. This model includes thermal motions and molecular deformations. Several crystalline structures with monoclinic symmetry P21/c have been found by the calculation. Factors which influence the stability of these structures are investigated. The lowest-energy structure, labeled I, agrees with the experimental one. Calculated crystal and molecular parameters agree with data determined by x-ray diffraction at 296 K. While no temperature-induced phase transition has been found from 296 to 124 K at ambient pressure, a phase transformation has been evidenced numerically at 0.43 GPa and 296 K. The monoclinic pressure-induced phase, stable above 0.43 GPa, is labeled II. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.477790
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  • 2
    Electronic Resource
    Electronic Resource
    High pressure solid phases of benzene. III. Molecular packing analysis of the crystalline structures of C6H6 (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 9079-9089 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: With a computer simulated mechanical model for molecular packing analysis, the reconstitution and identification of the intermediate pressure-induced phase II of solid benzene C6H6 at 293 K, has been undertaken. The atom-atom intermolecular potential of the Buckingham type was generalized to account for short interatomic distances, especially under pressure. The model includes thermal motion and molecular deformation effects. Various crystal structures calculated in the pressure range of phase II and checked by their reticular distances and structure factors, are compared with the structure IIo proposed for this phase. Among them two possible monoclinic structures IIc and IIc′ have been evidenced by the calculation. Structure IIc has energy and enthalpy levels lower than that of phases Ic and IIIc, in the pressure range 0.5〈P〈1.0 GPa. This allows to suggest this stable monoclinic structure IIc for the real structure of the experimentally observed phase II. This structure IIc corresponds to the structure previously determined as metastable by Dzyabchenko and Bazilevskii [J. Struct. Chem. 26, 553 (1985)]. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471441
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  • 3
    Electronic Resource
    Electronic Resource
    Raman spectra of solid CH4 under high pressure. III. New high pressure phases in solid CH4 and CD4 (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 6165-6172 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have observed the Raman spectra of the intramolecular vibrations in solid CH4 and CD4 at T=4.2 K under high pressure. For solid CH4, the spectra changed markedly at P(approximately-equal-to)9 kbar, indicative of a new phase VI above this pressure. For solid CD4, an analogous change was observed at P(approximately-equal-to)5.4 kbar, indicating a phase transition from phase III to a new phase IV. The spectra of these new phases, CH4 VI and CD4 IV, are very similar so that it is concluded that the crystal structures of the phases are isomorphous. The observed spectra seem to indicate that the molecular orientations of methane molecules in the new high pressure phases are fully ordered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449612
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  • 4
    Electronic Resource
    Electronic Resource
    High pressure solid phases of benzene. I. Raman and x-ray studies of C6H6 at 294 K up to 25 GPa (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 4255-4271 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Crystalline benzene has been investigated at room temperature as a function of pressure up to 25 GPa in diamond anvil cells by Raman scattering and powder x-ray diffraction techniques. The concomitant spectroscopic and crystallographic results show the existence of numerous pressure-induced phases. Changes in the profiles of the Raman spectra and in the x-ray diffraction patterns, as well as changes in the variations of the Raman frequencies and the cell parameters with pressure indicate two first-order phase transitions at 1.4±0.1 and 4±1 GPa and a second-order one at 11±1 GPa. At 24 GPa the x-ray diffraction pattern seems to indicate the existence of a new phase. Two monoclinic structures are proposed for the phases above 1.5 GPa, in addition to the already known one. From these data, molar volume has been determined as a function of pressure and the Grüneisen parameters have been inferred in the different phases. Their pressure dependences are analyzed in the light of theoretical predictions. Arguments are given for a phase transformation at normal pressure and below 140 K or at room temperature below 1 GPa. A schematic P–T phase diagram is suggested and a controversy on the nature of the triple points located on the melting curve is clarified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454809
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  • 5
    Electronic Resource
    Electronic Resource
    Transformation of benzene to a polymer after static pressurization to 30 GPa (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 6910-6915 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: After pressurization to 30 GPA, in a diamond anvil cell, benzene transforms, at room temperature, to a white solid which is stable at ambient pressure. We report here the infrared spectroscopy analysis performed under pressure and at ambient conditions. These preliminary results show that the transformation involves an opening of the benzene rings leading to a highly cross-linked polymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458278
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  • 6
    Electronic Resource
    Electronic Resource
    High pressure solid phases of benzene. II. Calculations of the vibration frequencies and evolution of the bonds in C6H6 and C6D6 up to 20 GPa (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 96 (1992), S. 2633-2654 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The complete vibrational spectra of crystalline C6H6 and C6D6 have been calculated for the different pressure-induced solid phases recently determined at 293 K up to 25 GPa, and compared to Raman scattering data. The normal coordinate analysis has been carried out by using intermolecular Buckingham-type atom–atom interactions and the intramolecular force field of the free molecule. Results of such frequency calculations are compared to experimental values at ambient pressure. The variation of the relevant crystalline parameters is discussed to construct a model and calculate the vibrational frequencies under pressure. The quantitative fit of the frequency shift of the Raman active modes under pressure demonstrates the necessity of including different C–C and C–H (C–D) bond compressibilities within the benzene molecule. Such intramolecular distance variations which allow to estimate the frequency corrections for the totally symmetric (a1g) breathing modes, have been determined from the observed pressure-frequency dependence of these internal modes. The behavior of other nonsymmetric (e2g) internal modes which become comparatively weak under pressure, suggests a charge delocalization within—and possibly out of—the benzene ring, eventually leading to irreversible opening of the hexagonal cycle. This can be directly related to the irreversible transformation of benzene to a polymer which is observed after pressurization above 20 GPa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.462014
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  • 7
    Electronic Resource
    Electronic Resource
    A rapid gas chromatographic determination of thiamphenicol in plasma and amniotic fluid
    Amsterdam : Elsevier
    Journal of Chromatography A 121 (1976), S. 243-250 
    Details
    ISSN: 0021-9673
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0021-9673(00)85020-7
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  • 8
    Electronic Resource
    Electronic Resource
    Raman spectra of solid benzene under high pressure
    Amsterdam : Elsevier
    Solid State Communications 54 (1985), S. 95-97 
    Details
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0038-1098(85)91042-7
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  • 9
    Electronic Resource
    Electronic Resource
    Enzymatic Dedifferentiation of Neoplastic Cells (1963)
    [s.l.] : Nature Publishing Group
    Nature 197 (1963), S. 1312-1313 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] In this investigation squamous cell carcinoma was induced in the cervix and upper vagina of adult virgin C3H N mice by twice-weekly painting of the ectocervix with a 1 per cent suspension of 3,4-benzpyrene in acetone. After fewer than 40 treatments all the animals showed invasive neoplasms. A ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/1971312a0
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  • 10
    Electronic Resource
    Electronic Resource
    Fine Structure of the Nuclear Envelope of Carcinoma Cells (1958)
    [s.l.] : Nature Publishing Group
    Nature 182 (1958), S. 1030-1031 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Those considerations about the continuity of the lumen of the endoplasmic reticulum and the peri-nuclear cisterna are based on electron micrographs of acinar cells of the pancreas, of parenchymatous liver cells and phagocytes and of Rous tumour cells3. It was suggested that a relation exists ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/1821030a0
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