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  • Optical activity  (2)
  • Irreversible process  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical chemistry accounts 41 (1976), S. 95-117 
    ISSN: 1432-2234
    Keywords: Irreversible process
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The “Principle of Increasing Mixing Character”, previously postulated by one of us (and derived for the case of an ensemble of isolated systems obeying a “master equation”) as a stronger version of the second law of thermodynamics, is re-derived using von Neumann's density matrix formulation of statistical mechanics. To make the principle more convenient for applications, it is reformulated in terms of “Mixing Homomorphic Functions”, a set of state functions all of which must increase in an allowed irreversible process in an-isolated system. The entropy is one such function, but no one function, and no finite set of functions, suffices to determine the increase of mixing character. The principle is extended to the case of a system which is not isolated, but in contact with a heat bath, for which it takes a form which we name the “Principle of Decreasing Mixing Distance” from the equilibrium distribution. As examples, applications are made to two simple cases: diffusion in an ideal solution, and chemical reactions in ideal gas mixtures.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0570-0833
    Keywords: Chirality functions ; Optical activity ; Allene derivatives ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A comparison of calculated and experimental data shows that the optical rotatory power of phenylallenecarboxylic acids is quantitatively described by the polynomial expression developed in (1). The Td component of this expression, the only relevant one for the case of methane derivatives turns out to be negligibly small in the case of allene derivatives. Therefore, and because allene derivatives belong to category a[16] the sequence of the λ-parameter values of the ligands may be used to determine the configuration and the sign of rotation.
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0570-0833
    Keywords: Chirality functions ; Optical activity ; Methane derivatives ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optical activity can provide detailed information about the configuration and conformation of methane derivatives if the chirality function is resolved, according to the theory of chirality functions[3] and the quantum mechanical theory of the optical activity of methane derivatives[4], into its components which are compared with experimental data. A first step in this direction is undertaken in the present article and it will be shown that the second approximation method for determining the conformationally independent contribution to the optical activity yields quantitatively good results. Description of the overall optical rotation by this component is expectedly poor where interactions between ligands, e. g. hydrogen bonding, tend to favor specific conformations. A quantitative understanding of such additional effects appears promising in conjunction with analyses of the kind described.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
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