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  • 1
    Electronic Resource
    Electronic Resource
    Vibrational spectroscopy of dispersed silica: Aerosil (1993)
    Springer
    Journal of structural chemistry 33 (1993), S. 536-544 
    Details
    ISSN: 1573-8779
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions A complex experiment has been carried out to examine the vibrational spectrum of Aerosil, and it has been found that the silanol group is the main active center of this type of dispersed silica. This fact conforms well with the previously advanced supposition that the structure of the core of silica is of a closed type in this case. The experimentally measured vibrational spectrum of the adsorbed water is practically completely described by a model in which one silanol center reacts with a water cluster. This agrees with the fact that chemical hydrophobic reactions take place on the surface of the usual commercial, i.e.,wet Aerosil. Since water is adsorbed as a cluster around one center, then in the presence of the usual 2. wt. % of water, a large part of the surface will be free of water and available for other reactions. It is natural that the above-considered simple models do not permit explanation of all the details of the observed spectra and a large amount of work will have to be carried out with more complicated models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00746931
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  • 2
    Electronic Resource
    Electronic Resource
    Vibrations of dispersed silicas: A comparative (1993)
    Springer
    Reaction kinetics and catalysis letters 50 (1993), S. 221-226 
    Details
    ISSN: 1588-2837
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Four families of disperse amorphous silica representing different solid species modifications have been studied by inelastic neutron scattering at 10, 80 and 290 K. Doubly amplitude-weighted density of vibrational states (AWDS) have been obtained from the experimental time-of-flight spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02062215
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  • 3
    Electronic Resource
    Electronic Resource
    Method for the construction of basis spectra of multicomponent systems. The zero correlation coefficient criterion (1993)
    Springer
    Journal of structural chemistry 34 (1993), S. 37-45 
    Details
    ISSN: 1573-8779
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new method is proposed for factoring the spectrum of a multicomponent system when the basis spectra of its components are unknown and the set of the weighting coefficients in the initial spectrum is incomplete. At the basis of this method is the postulate that there is no correlation between the basis spectra. A physically significant basis is constructed by linear algebra methods using this postulate. The components of the basis satisfy the zero linear correlation coefficient criterion. This method was successfully tested for two two-component systems, whose basis spectra are a priori not correlated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00745400
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  • 4
    Electronic Resource
    Electronic Resource
    Construction of vibrational basis spectra of multicomponent systems 1. Aerosil (1993)
    Springer
    Journal of structural chemistry 34 (1993), S. 46-55 
    Details
    ISSN: 1573-8779
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Aerosil (pyrogenous dispersed silica) is considered as a three-component system consisting of a silica core, hydroxyl shell, and adsorbed water. Factoring was carried out for its amplitude-weighted vibrational state density (AWSD) spectra obtained using inelastic neutron scattering at 10 K into the spectra of the components comprising this system. The factoring method used is based on the postulate of lack of correlation of the basis spectra. The factoring was carried out by the construction of physically significant basis spectra satisfying the zero linear correlation coefficient criterion for a set of AWSD spectra of the starting and modified samples of Aerosil A380.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00745401
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  • 5
    Electronic Resource
    Electronic Resource
    Construction of vibrational basis spectra of multicomponent systems 2. Silica gel (1993)
    Springer
    Journal of structural chemistry 34 (1993), S. 56-67 
    Details
    ISSN: 1573-8779
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Silica gel is considered a three-component system consisting of a silica core, hydroxyl shell, and pore-retained water. Inelastic neutron scattering was used to obtain a set of amplitude-weighted vibrational state density (AWSD) spectra of two silica gel families SG20 and SG100 with mean pore diameter of 20 and 100 Å, respectively. The AWSD spectra were factored into the components of this system. The factoring method used is based on the postulate of lack of correlation of the basis spectra. The factoring was carried out by the construction of physically significant basis spectra satisfying the zero linear correlation coefficient criterion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00745402
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  • 6
    Electronic Resource
    Electronic Resource
    Construction of basis vibration spectra of multicomponent systems. 3. Aerogel (1994)
    Springer
    Journal of structural chemistry 34 (1994), S. 513-522 
    Details
    ISSN: 1573-8779
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Capillary-hollow silica (aerogel) is regarded as a three-component system consisting of the silica core, the hydroxyl component, and absorbed water. Its spectra of the doubly amplitude-weighted density of vibration states (AWDS), recorded at 10 K using the inelastic neutron scattering, were aecomposed into the spectra of the components of the system. The study uses the difference correlation technique based on the postulated lack of correlation between the basis spectra. The decomposition has been made by constructing physically significant basis spectra satisfying the criterion of zero coefficient of linear correlation, for the starting and modified samples of aerogel AG200.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00753519
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  • 7
    Electronic Resource
    Electronic Resource
    Comparative analysis of vibration spectra of dispersive silicas and their components (1994)
    Springer
    Journal of structural chemistry 34 (1994), S. 523-533 
    Details
    ISSN: 1573-8779
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Comparative analysis has been carried out on a set of partial basis spectra of the doubly amplitude-weighted density of vibration states (AWDS) of four dispersive silica: aerosil A380, silica gels SG20 and SG100 (with pore sizes 20 and 100 Å), and aerogel AG200 with mass density 200 kg/m3. The set of basis spectra includes the vibration spectra of frameworks, and of the hydroxyl and aqueous components of the surface zone of the above compounds. Aerosils, silica gels, and aerogels have been found to be radically different structural forms of amorphous silica, both from the viewpoint of their frameworks and their surface zones. The basis spectra considered represent a collection of “fingerprints” of the structure-dynamic properties of the compounds studied, which allows us to formulate a qualitatively new approach to computational modeling of dispersive silicas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00753520
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  • 8
    Electronic Resource
    Electronic Resource
    The electronic states of naphthalene molecules adsorbed on a zeolite (1969)
    Springer
    Theoretical and experimental chemistry 3 (1969), S. 220-223 
    Details
    ISSN: 1573-935X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Physical principles are considered for this method of examining interactions. Changes in absorption and fluorescence spectra are examined in relation to Van der Waals, electrostatic, and exchange interactions. Major spectral criteria are presented for the types of interaction and are illustrated by reference to naphthalene adsorbed on zeolites. Spectra at 77
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00525603
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  • 9
    Electronic Resource
    Electronic Resource
    Luminescence spectra and adsorption characteristics of naphthalene on various metal-substituted forms of type X zeolite (1972)
    Springer
    Theoretical and experimental chemistry 5 (1972), S. 156-158 
    Details
    ISSN: 1573-935X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The low-temperature luminescence spectra of samples obtained after adsorption of naphthalene by metal-substituted type X zeolites are examined. In zeolites of the first group (LiNaX, NaX, KNaX, RbNaX, CsNaX, MgNaX, CaNaX, ZnNaX, SrNaX, and BaNaX), the luminescence spectra of all the systems studied are largely the same. In the analysis of these spectra, naphthalene molecules which are physically sorbed and those bound by donor-acceptor interaction are distinguished. In forming the adsorbed charge-transfer complex (CTC), the naphthalene molecules behave as electron donors. The elements of the zeolite lattice serve as the acceptors. With zeolites of the first group, oxidation of the anphthalene, occurring in the adsorbed phase on contact with air, is observed spectroscopically. In constrast, zeolites of the second group (CoNaX, NiNaX, CuNaX, AgNaX, and CdNaX) are characterized by individual spectra due to the formation of a CTC between the naphthalene molecule and the metal present in the lattice. None of the five systems displayed oxidation of the naphthalene on contact with air.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00528039
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  • 10
    Electronic Resource
    Electronic Resource
    Computer modeling of assembly of atoms in an electric field (1996)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 57 (1996), S. 741-755 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A computer modeling of events that occurred under the scanning tunneling microscope (STM) tip was considered from a chemical standpoint. The DYQUAMOD, semiempirical dynamical-quantum chemical program system, which well manifested itself in a quantitative studying of nano-sized objects, was transformed into the DYQUAFIELD program system involving an external electrostatic field. The fields of changeable configurations were simulated by a set of up to 200 point charges. Atomic system modeling was focused on obtaining local electron density (LED) as well as on the object chemical transformations caused by the field. This article presents the results of simulating LED of differently originated graphite films, of a field action on a set of stable molecules, and of an irreversible in-field reconstruction of the diamondlike film surface, which demonstrates a possible nano-sized memory element creation. © 1996 John Wiley & Sons, Inc.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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