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  • 1
    Electronic Resource
    Electronic Resource
    The lattice dynamics of β-hydroquinone clathrate (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 2773-2778 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Dynamic properties of β-hydroquinone (Qβ) clathrate with various guest molecules have been calculated by the method of lattice dynamics within the atom–atom potential approximation; van der Waals interactions, H-bond interactions, and electrostatic interactions for charges localized on the atoms are included. External vibration spectra have been calculated for the empty framework of Qβ and with different guest molecules (HCN, CO2, SO2, C2N2, C2H6, CH3OH, O2CO). Vibrational frequencies of the guest molecules in cavities are determined. The phonon density of states for these compounds has been calculated. The influence of the encaged guest molecules on the vibrational spectrum of the host lattice has been investigated. The most visible changes are observed upon the insertion of guest molecules with large dipole moment or those positioned asymmetrically inside the Qβ clathrate cages. Peculiarities of different interactions have been revealed. Analysis of the calculated and experimental results have been carried out. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.470513
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  • 2
    Electronic Resource
    Electronic Resource
    The mechanisms for pressure-induced amorphization of ice I h (1999)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 400 (1999), S. 647-649 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] There has been considerable interest in the structure of liquid water at low temperatures and high pressure following the discovery of the high-density amorphous (HDA) phase of ice Ih (ref. 1). HDA ice forms at a pressure close to the extrapolated melting curve of ice, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/23216
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  • 3
    Electronic Resource
    Electronic Resource
    Electronic structure of linear chains of fullerenes (1997)
    Springer
    JETP letters 65 (1997), S. 683-686 
    Details
    ISSN: 1090-6487
    Keywords: 61.48.+c ; 71.20.Tx
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The band structure of linear chains of fullerene molecules is calculated as a function of the intermolecular π-electron overlap integral T, which increases under increasing external pressure. Chains consisting of neutral (C60) and charged (C 60 − ) molecules are studied. It is shown that there is a sharp transition from a metal (or narrow-gap semiconductor) to an insulator (with band gap ∼1 eV)with increasing T. The proposed model makes it possible to describe the formation of solid-carbon struc-tures, containing chains of covalently bound fullerene molecules, with different pressure-dependent semiconductor properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567406
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  • 4
    Electronic Resource
    Electronic Resource
    Polarons in linear chains of fullerenes (1996)
    Springer
    JETP letters 64 (1996), S. 567-572 
    Details
    ISSN: 1090-6487
    Keywords: 75.10.Jm ; 75.30.Ds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Polaron states in linear chains of fullerenes are studied with the use of the generalized model of Su-Shrieffer-Heeger (SSH) for the intermolecular and intramolecular degrees of freedom. Electron charge distributions over the molecular surface and Jahn-Teller distortions of carbon atoms in C60 are calculated self-consistently for linear C60 polymer and C 60 − polyanion chains. A polaron band narrowing is examined. It is shown that the polymerization of C60 molecules in phase transitions may be caused by the cooperative Jahn-Teller effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.567263
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  • 5
    Electronic Resource
    Electronic Resource
    Dynamics of the C60 molecule (1994)
    Springer
    Journal of structural chemistry 34 (1994), S. 634-637 
    Details
    ISSN: 1573-8779
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00753536
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  • 6
    Electronic Resource
    Electronic Resource
    Finite-temperature Green's functions of the fluctuation electromagnetic field of a sphere and spherical layer imbedded in an infinite medium (1976)
    Springer
    Theoretical and mathematical physics 28 (1976), S. 858-862 
    Details
    ISSN: 1573-9333
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01029179
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  • 7
    Electronic Resource
    Electronic Resource
    The description ofP, T, X-phase diagrams in systems with clathrate formation where the guest-guest interaction is taken into account. Hydroquinone-noble gas systems (1984)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 1 (1984), S. 251-262 
    Details
    ISSN: 1573-1111
    Keywords: Clathrate ; calculation of the Phase Diagram of binary systems ; the role of the guest-guest interaction ; thermodynamics ; hydroquinone-noble gas systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract We discuss phase equilibria in the binary guest-host system with clathrate formation where the guest-guest interaction is taken into account. The equations for phase equilibria in this system are derived for the general case, where the initial host α-modification can include guest molecules, and where the host molecules can form several metastable clathrate frameworks whose energies do not differ greatly from one another and from the stable form. We have applied these equations to the binary noble gas-hydroquinone systems for which the equations simplify considerably. This allowed us to calculateP, T, X-phase diagrams for these systems and to compare them with the diagrams obtained experimentally. The model employed describes experimental results not only qualitatively (e.g., the increase of the melting temperature of the hydroquinone α-modification with increasing content of the guest) but also quantitatively. It has been shown that consideration of guest-guest interaction even in the hydroquinone systems, in which this interaction is relatively small, improves the description of the phase diagrams.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656760
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  • 8
    Electronic Resource
    Electronic Resource
    Hydroquinone clathrates and the theory of clathrate formation (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 243-260 
    Details
    ISSN: 1573-1111
    Keywords: Clathrate ; theory of clathrate formation ; hydroquinone clathrate ; the role of the guest-guest interaction ; statistical thermodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The model of a clathrate solid solution, taking into account directed and nondirected guest-guest interactions, has been obtained using statistical thermodynamic methods in the approximation of the mean-field type for the general case (the formation of cavities of several types and the inclusion of different kinds of guest molecules by the host). Consideration of this interaction has been shown to improve the quantitative agreement between theory and experiment. When the guest-guest interaction is considerable in the case of guest molecules of the same type a phase transition (of a gas-liquid type) of the guest component may occur in the clathrate matrix. In the case of guests of two different types, the phase transition of the guest subsystem of the liquid-liquid type may also occur within one framework at the expense of a preferable interaction among guest molecules of the same type. We present the isothermal (20°C) section of the phase diagram of a hydroquinone-— formic acid — acetonitrile system. Clathrates, forming in the binary systems (with hydroquinone) produce restricted solid solutions (of type IV, according to Roozeboom). These and other experimental data are discussed in terms of the proposed theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655728
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  • 9
    Electronic Resource
    Electronic Resource
    Clathrate thermodynamics for the unstable host framework (1987)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 5 (1987), S. 195-202 
    Details
    ISSN: 1573-1111
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract We have introduced the concept of clathrates whose empty host framework is unstable. In contrast to the Van der Waals theory, according to which the empty host framework is metastable, we believe it to become metastable when, in the cellular clathrates, certain type of cavities are fully occupied or, in the channel clathrates, the guest molecules are closely packed. The free energy of the channel and cellular types of clathrates has been determined using statistical thermodynamics methods. The obtained chemical potentials allowed us to describe the equilibrium of the clathrate with the stable host α-phase and the gaseous guest phase. For the cellular clathrates the equations have been obtained determining the dependence of the degree of filling of small cavities upon temperature and the gaseous phase pressure. In the case of the channel clathrates the set of equations on the composition and parameter of the orientational ordering is found. These equations enable us to describe quantitatively compressed state of the guest molecules in the channel and to find temperatures of orientational ordering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655648
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  • 10
    Electronic Resource
    Electronic Resource
    Theory of Clathrates (1991)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 10 (1991), S. 399-422 
    Details
    ISSN: 1573-1111
    Keywords: Clathrate ; ideal and non-ideal clathrate solutions ; phase diagrams ; guest-guest interaction ; instability of empty host framework
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A review is presented of the theory of clathrate compounds, starting with the first quantitative theory suggested by van der Waals and Platteeuw and ending with the current ideas. A brief description is given of the theory of ideal and non-ideal solid clathrate solutions and of the theory allowing us to describe clathrates with an unstable, empty host lattice. The review is composed of results obtained by the different methods based on various approximations. In the concluding section predictions are made of the further development of the theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01061072
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