First-principles Raman spectroscopy of dissolved carbon in water under extreme conditions

ORAL

Abstract

The aqueous properties of dissolved carbon at extreme conditions are of great importance to the carbon cycle in the deep Earth, which substantially influences the carbon budget near the Earth's surface, and in turn global climate change. We carried out first-principles simulations that showed that, contrary to the assumptions of many geochemical models, carbon dissolved in water-rich fluids at the bottom of the Earth's upper mantle is not in the form of CO$_2$(aq) but rather in carbonate and bicarbonate ions [1]. We also calculated the Raman spectra of (bi)carbonate aqueous solutions at supercritical conditions, and obtained the Raman scattering cross sections of carbon species at high pressures and high temperatures from first principles. We will discuss how to use our results to interpret and guide spectroscopic measurements. [1]D. Pan and G. Galli, Sci. Adv. 2, e1601278(2016)

*The work is supported by the Sloan Foundation through the Deep Carbon Observatory and the US DOE through the MICCoM.

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Authors

  • Ding Pan

    • Hong Kong University of Science and Technology
    • Department of Physics and Department of Chemistry, Hong Kong University of Science and Technology

  • Giulia Galli

    • Univ of Chicago and Argonne National Laboratory
    • Univ of Chicago
    • University of Chicago; Argonne National Laboratory
    • Institute for Molecular Engineering, University of Chicago; Argonne National Laboratory
    • Institute for Molecular Engineering, University of Chicago and Materials Science Division, Argonne Natl Lab
    • Institute for Molecular Engineering, University of Chicago; Materials Science Division, Argonne National Laboratory
    • Institute for Molecular Engineering, University of Chicago, Chicago, IL 60637 and Materials Science Division, Argonne National Laboratory, Lemont, IL
    • Institute for Molecular Engineering, University of Chicago and Argonne Natl Lab
    • University of Chicago, Chicago, IL 60637, USA
    • The University of Chicago, Institute for Molecular Engineering and Argonne National Laboratory
    • Argonne National Laboratory and University of Chicago
    • Institute for Molecular Engineering, University of Chicago and Materials Science Division, Argonne National Laboratory
    • University of Chicago
    • The University of Chicago
    • University of Chicago and Argonne National Laboratory