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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 52 (1987), S. 3200-3205 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 57 (1992), S. 790-792 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 2536-2547 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Reactions of H atoms with N2O have two product channels yielding NH+NO and OH+N2. Both channels were observed via NH A 3Π←X 3∑ and OH A 2∑←X 2Π laser-induced fluorescence spectra. Photoinitiated reactions with N2O–HI complexes yield a much lower [NH]/[OH] ratio than under the corresponding bulk conditions at the same photolysis wavelength. For hot D-atom reactions with N2O, this effect is somewhat more pronounced. These results can be interpreted in terms of entrance channel geometric specificity, namely, biasing hydrogen attack toward the oxygen. Another striking observation is that the OH and OD rotational level distributions (RLD) obtained under bulk conditions differ markedly from those obtained under complexed conditions, while the NH as well as the ND RLD are similar for the two environments. In addition, OH Doppler profiles change considerably in going from bulk to complexed conditions, while such an effect is not observed for NH. The changes observed with the OH RLD are most likely due to OH–halogen interactions and/or entrance channel specificity. Under bulk conditions, the Doppler shift measurements indicate a large amount of N2 internal excitation (i.e., ∼25 000 cm−1) for the OH (v=0) levels monitored. This is consistent with a reaction mechanism involving an HNNO° intermediate. The hot hydrogen atom first attaches to the terminal nitrogen of N2O and forms an excited HNNO° intermediate having a relatively elongated N–N bond compared with N2O. Then the H atom migrates from nitrogen to oxygen and exits to the N2+OH product channel, leaving N2 vibrationally excited. A simple Franck–Condon model can reconcile quantitatively the large amount of N2 vibrational excitation.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 7397-7401 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Dielectric measurements on quenched (C2F6)1−x (CClF3)x fluorocarbon alloys are reported. In a wide concentration range, rapid cooling prevents these samples from unmixing and the plastic phase, characterized by translational order and orientational disorder, can be supercooled. The relaxation dynamics of crystals with x=0.32 is examined in detail. For temperatures below 50 K it exhibits a dominant primary and indications of secondary relaxation, i.e., typical features of glasses. The α-relaxation process is parametrized in terms of a modified Vogel–Fulcher law. Using this representation, (C2F6)0.68(CClF3)0.32 can be characterized as fragile glass according to Angell's classification scheme.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 4981-4986 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Dielectric measurements were performed on liquid and solid (CF4)1−x (CMF3)x with M=H, Cl, and Br. The dielectric behavior of the polar molecules in the liquid state is well described by an Onsager equation. At the melting point, pure hydrogenated and brominated fluoromethanes condense into dipolar rigid phases, while pure tetrafluoromethane forms a plastic crystal. CClF3 exhibits dipolar relaxational phenomena in the solid state. The data indicate that near the melting point this compound is close to a transition into a plastic phase. Mixtures of CF4 with CHF3 and CBrF3 exhibit monotectic phase diagrams with a limited solubility in the liquid state and complete immiscibility in the solid state. However, formation of mixed crystals is found in (CF4)1−x (CClF3)x which exhibits a eutectic phase diagram.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 2143-2148 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Solid solutions of (C2F6)1−x(CClF3)x were investigated using dielectric spectroscopy. In part I of this work results on thermally equilibrated (C2F6)1−x(CClF3)x alloys are presented. The molar polarizability of liquid and plastic C2F6 was determined. The phase diagram of (C2F6)1−x(CClF3)x was studied in detail. It exhibits two eutectic points and a large miscibility gap. In a high-temperature orientationally disordered phase mixed crystals can be grown up to CClF3 concentrations x≈0.5; in the low-temperature ordered state solid solutions are stable for x≤0.25. The dielectric loss spectra indicate that in (C2F6)1−x(CClF3)x different relaxation channels are available for the CClF3 dipoles.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 3111-3118 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: (CF4)1−x(CClF3)x shows a eutectic phase diagram with a eutectic temperature TE =69 K and a eutectic concentration xE =0.54. In the mixed crystal regime x〈0.015, dielectric audio frequency spectroscopy revealed the dynamics of weakly coupled CClF3 molecules performing thermally activated reorientations. An analysis of the data was performed in terms of a relaxator model including a critical comparison of different distributions of relaxation times. The static susceptibilities of the mixed crystals suggested a two-phase model of CF4, where rigid latice domains coexist with paraelastic regions. Several pure CClF3 samples were investigated using different thermal treatments. The dielectric dispersion of this compound is described by the reverse Havriliak–Negami expression and possible explanations for the origin of the relaxation spectra are discussed. The behavior of the CClF3 rich mixed crystals is considered briefly.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 99 (1993), S. 6545-6552 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Reactions of photolytically prepared hot deuterium atoms with OCS have been investigated: (i) under gas phase, single collision, arrested relaxation (i.e., bulk) conditions; and (ii) by photoinitiating reactions within weakly bound OCS–DI complexes. Nascent SD(X 2Π, v=0) rotational, spin–orbit, and Λ-doublet populations were obtained for the photolysis wavelengths 250, 225, and 223 nm by using A 2Σ←X 2Π laser induced fluorescence (LIF). The reason for using deuterium is strictly experimental: A 2Σ predissociation rates are considerably smaller for SD than for SH. The SD (v=0) rotational distribution was found to be very cold and essentially the same for both bulk and complexed conditions; the most probable rotational energy is ∼180 cm−1. No bias in Λ-doublet populations was detected. Spin–orbit excitation for bulk conditions was estimated to be [2Π1/2]/[2Π3/2]∼0.25, where 2Π1/2 is the upper spin–orbit component. This ratio could not be obtained with complexes because of limited S/N. The complete set of present and past experimental findings, combined with recent theoretical results of Rice, Cartland, and Chabalowski suggest a mechanism in which SD derives from a very short lived HSCO precursor. This can result from direct hydrogen attack at the sulfur and/or the transfer of hydrogen from carbon to sulfur via the HCOS intermediate.
    Type of Medium: Electronic Resource
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