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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 73 (2002), S. 1602-1604 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The medium energy x-ray double crystal monochromator (DCM) is currently being designed at the Canadian Light Source (CLS). Design goals for the DCM are to provide photons between 1750–5500 eV with a resolving power better than 3000 and photon flux better than 5×1010 photons/s/0.1% bandwidth for 500 mA beam current. A set of indium antimonide crystals [InSb(111)] will be used over the energy range of 1750–3700 eV, with resolution ranging from 0.52–1.05 eV. Although InSb allows one to probe the important silicon K edge at ∼1840 eV, it has the disadvantage of poor thermal conductivity. Exposure to high heat loads from the CLS synchrotron on the first crystal (∼56.5 W of power for 2 mrad of horizontal bending magnet radiation, ∼0.54 W/mm2 power density) will cause crystal distortion and thereby intensity/resolution degradation. A second set of silicon crystals [Si(111)] are proposed for the energy range of 3700–5500 eV. Resolution ranges linearly from ∼0.41 to ∼0.70 eV over this energy range. A harmonic filter mirror has been included in the design to reject higher harmonic orders. SHADOW ray-tracing results show that the experimental focus should be 334 μm [horizontal full width at half-maximum (FWHM)]×296 μm (vertical FWHM) when the CLS is operational under 2008 conditions. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3840-3850 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Using monochromatized synchrotron radiation, gas phase photoelectron spectra of CF3I have been obtained between 21 and 100 eV photon energies. Experimental valence band branching ratios have been compared with theoretical branching ratios from MS-Xα calculations. The generally good agreement between experiment and theory confirms the orbital assignment: 4e〈4a1〈1a2∼3e〈2e〈3a1〈1e∼2a1 〈1a1, in order of increasing binding energy. In contrast to CF4, MS-Xα calculations predict two shape resonances for CF3I at 15.2 eV (e channel) and 17.2 eV (a1 channel). Experimentally, weak shape resonances are observed on e orbitals at ∼14 eV kinetic energy. The cross sections are very useful for correlating orbitals in CF3I with those of CF4. For example, the cross sections suggest that the 3e orbital in CF3I correlates with the 1t1 orbital rather than the 4t2 orbital in CF4. After the onset of the I 4d level at ∼57 eV, intershell coupling becomes important in enhancing valence band levels having high I 5p character such as the 4e orbital. The I 4d branching ratio from 66 to 110 eV is similar to the Xe 4d branching ratio in atomic Xe, indicating atomic-like behavior for the I 4d subshell.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 4906-4916 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Using monochromatized synchrotron radiation, the gas phase photoelectron spectra of the five valence orbitals of CF4 and SiF4 have been obtained from 21 to 100 eV photon energies. Branching ratios (BR) for both molecules, and partial cross sections (σ) for CF4, have been obtained from these spectra. The agreement between our σ values for CF4 and previous results is excellent. Theoretical branching ratios, partial cross sections, and β values have been obtained from MS Xα calculations, and compared with experiment. The generally good agreement between experiment and theory for SiF4 confirms the orbital assignment: 1t1〈5t2〈1e〈4t2〈5a1, in order of increasing binding energy. In contrast to the CF4 results which show little structure, five shape resonances are predicted for SiF4, at 3, 7, 13, 23, and 35 eV kinetic energies. The predicted resonance positions and intensities are in good agreement with experiment (e.g., for the 23 and 35 eV resonances), but the low energy resonance positions and intensities are usually not well reproduced experimentally. The radically different resonance features in CF4 and SiF4 are discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 87 (1987), S. 821-829 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Using monochromatized synchrotron radiation, the gas phase photoelectron spectra of the Hg 5d and valence levels of Hg(CH3)2 have been obtained between 21 and 100 eV photon energies. Experimental valence band branching ratios have been compared with theoretical branching ratios from MS-Xα calculations. Our results strongly suggest that the ordering of valence levels is 2a‘2〈3a1〈2e'〈2e‘, rather than 2a‘2〈3a1〈2e‘〈2e' from previous theoretical calculations. For the 3a'1 orbital, two shape resonances are predicted at 30 and 50 eV kinetic energy. Only the one at 30 eV is observed. Interchannel coupling with Hg 5d photoemission is important for the outermost 2a‘2 and 3a'1 orbitals. Shape resonances and interchannel coupling strongly suggest that He ii:He i cross section ratios cannot generally be used to infer orbital character. The Hg 5d intensity ratio in Hg(CH3)2 differs from that of atomic Hg in the low photon energy region. This effect is probably due to the differences in the outgoing f wave potential between Hg and Hg(CH3)2.
    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 84 (1986), S. 5-9 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Using monochromatized synchrotron radiation and angle integrated photoelectron spectroscopy, the Si 2p, Si LVV Auger, and F 2s cross sections have been obtained for SiF4 molecules in the gas phase between 116 and 150 eV photon energies. These cross sections and the Si 2p β value have also been calculated using the MS-Xα method. There is qualitative agreement between theory and experiment. Together with recent experimental and theoretical Si 2p cross sections from SiCl4 and valence band cross sections on SiF4, the two major resonances at 5 and 22 eV kinetic energies are assigned as t2 resonances. The valence band branching ratios are not affected by interchannel coupling above the Si 2p threshold.
    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 84 (1986), S. 3603-3609 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Using monochromatized synchrotron radiation, the gas phase photoelectron spectra of the first five valence orbitals of XeF2 have been obtained from 21–50 eV photon energy. From these spectra, the branching ratios and partial cross sections have been calculated. Theoretical branching ratios and partial cross sections have been obtained from MS-Xα calculations and compared with experiment. The generally good agreement between experiment and theory confirms the DV-Xα and MS-Xα orbital assignments: 5πu 〈10σg 〈3πg 〈4πu 〈6σu, in order of increasing binding energy. Somewhat surprisingly because of the lack of antibonding virtual orbitals above threshold and the long Xe–F bond length (2.00 A(ring)), a number of strong resonances are predicted and observed. For example, resonances are predicted at 4.8 (πg channel), 11.6 (πu, δu channels), and 14.3 eV (σu channel) kinetic energies. The observed resonance positions are usually in reasonable agreement with these. The nature of these resonances are discussed, and compared to similar features in O2, F2, and CO2.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 957-959 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the x-ray absorption spectra for two hard carbon films grown by filament-assisted chemical vapor deposition in gas mixtures of 1% and 0.18% methane in hydrogen. Although the Raman spectra of these two films suggest significant differences in structure, the x-ray absorption near-edge structure and extended x-ray absorption fine structure (EXAFS) are very similar. Analyzing the EXAFS from these films with a diamond crystal as a reference gives carboncarbon bond lengths of 1.53±0.03 A(ring). This result is consistent with diamond and incompatible with graphite. We conclude that the carbon films have the same local structure as diamond.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 656 (1992), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 781 (1996), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 34 (1969), S. 2506-2508 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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