Browsing by Author "Ennis, C"

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    Condensed phase studies at the THz/Far-IR beamline at the Australian Synchrotron
    (Australian Institute of Physics, 2014-02-06) Appadoo, D; Ennis, C; Plathe, R
    The THz/Far-IR beamline at the Australian Synchrotron is coupled to a Bruker IFS125HR FT spectrometer equipped with a variety of optical components which can cover the spectral range from 5 to 5000 cm-1. Experiments from a variety of fields such as atmospheric and astrophysical science, geology, electrochemistry, nano-materials as well as biology have been successfully conducted at the beamline. There is a range of instruments to accommodate the diverse requirements of the User community. For gas-phase experiments, the beamline is equipped with multiple-pass optics gas-cells: one of which can be coupled to a furnace to study reactive species, while another can be cooled to liquid nitrogen or helium temperatures to study aerosols and cold gases. Users also have access to a couple of cryostats (one > 79 K, the other > 6 K), a grazing incidence angle optical setup and a near-normal accessory to study condensed phase systems, thin films and surface interactions. The synchrotron infrared light offers a S/N advantage over conventional thermal sources, but this advantage varies to a great degree upon the spectral range, sample size and resolution dictated by the application. In this paper, the capabilities and performance of the THz/Far-IR beamline at the Australian Synchrotron will be presented as well as some applications undertaken at the beamline, and future developments.
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    Crystal structure of propio­nitrile (CH3CH2CN) determined using synchrotron powder X-ray diffraction
    (International Union of Crystallography, 2020-01) Brand, HEA; Gu, QF; Kimpton, JA; Auchettl, R; Ennis, C
    The structure and thermal expansion of the astronomical molecule propio­nitrile have been determined from 100 to 150 K using synchrotron powder X-ray diffraction. This temperature range correlates with the conditions of Titan's lower stratosphere, and near surface, where propio­nitrile is thought to accumulate and condense into pure and mixed-nitrile phases. Propio­nitrile was determined to crystallize in space group, Pnma (No. 62), with unit cell a = 7.56183 (16) Å, b = 6.59134 (14) Å, c = 7.23629 (14), volume = 360.675 (13) Å3 at 100 K. The thermal expansion was found to be highly anisotropic with an eightfold increase in expansion between the c and b axes. These data will prove crucial in the computational modelling of propio­nitrile–ice systems in outer Solar System environments, allowing us to simulate and assign vibrational peaks in the infrared spectra for future use in planetary astronomy. © 2020 International Union of Crystallography