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  • 1
    Electronic Resource
    Electronic Resource
    Hydrogen bonding in long chains of hydrogen fluoride and long chains and large clusters of water molecules (1974)
    Springer
    Theoretical chemistry accounts 34 (1974), S. 115-127 
    Details
    ISSN: 1432-2234
    Keywords: (HF)n-chains ; (H2O)n-chains ; Hydrogen bond energies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Energy band structures of one-dimensional (HF)n- and (H2O)n-chains have been calculated (1) by extrapolation of CNDO/2-MO levels to infinite chain length and (2) by the CNDO/2 crystal orbital (CO) method. In the CO-calculations interactions up to fifth neighbours have been taken into account. Both types of calculations were performed using experimental geometries and CNDO/2 minimum geometries of the corresponding dimers (HF)2 and (H2O)2. With the same geometries CO calculations on two-dimensional sheets of hydrogen bonded chains were performed too. Due to end-effects the extrapolated MO bands are much broader than the bands obtained by the CO method. In the CO calculations further neighbour interactions play a non-negligible role and hence the nearest neighbour approximation is not sufficient for an accurate description of crystals containing hydrogen bonds. MO calculations on one-dimensional chains of both systems show that the hydrogen bond energies increase with the number of monomers indicating the presence of cooperative effects. The hydrogen bond energies calculated with the CO method are usually somewhat larger than those extrapolated from the MO results. In three-dimensional networks of (H2O)n, however, the additional stabilization of clusters with respect to dimers is drastically diminished.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00551362
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  • 2
    Electronic Resource
    Electronic Resource
    Theoretical investigation of semiconductive properties in proteins. II. The possibility of charge transfer between proteins and different acceptor molecules (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 899-908 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results of theoretical investigations are reported concerning the possibility of impurity-type charge carrier production in proteins. The energy band structures of the periodic protein model polyglycine calculated with the aid of the ab initio Hartree-Fock crystal orbital method and corrected afterwards for long-range correlation effects are compared with the empty levels of glyoxal, methyl-glyoxal, acrolein, and croton-aldehyde, suggested recently by Albert Szent-Györgyi as possible acceptors against proteins. The comparison with previous supermolecule calculations shows that appreciable charge transfer can be expected to glyoxal, methyl-glyoxal, and acrolein from the polypeptides, while croton-aldehyde is probably less efficient in this relation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180411
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