Cluster models of aqueous Na super(+) and Cl super(-) in sea water/ice

In this article, we present finite cluster models of aqueous solutes [NaCl(H sub(2)O) sub(10), NaCl(H sub(2)O) sub(5), and (H sub(2)O) sub(6)] in terms of molecular geometry and vibrational spectra for interpretation of experimental infrared spectra of NaCl brine solutions. The quantum chemistry pro...

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Bibliographic Details
Published in:Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology 2012-10, Vol.14 (10), p.1-9
Main Authors: Michelsen, R, Walker, R, Shillady, D
Format: Article
Language:English
Subjects:
Clusters
Halides
Infrared spectra
Marine
Mathematical models
Nanostructure
Quantum chemistry
Salt water
Sea water
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Summary:In this article, we present finite cluster models of aqueous solutes [NaCl(H sub(2)O) sub(10), NaCl(H sub(2)O) sub(5), and (H sub(2)O) sub(6)] in terms of molecular geometry and vibrational spectra for interpretation of experimental infrared spectra of NaCl brine solutions. The quantum chemistry program GAMESS is used to optimize the model clusters to a local minimum energy gradient of less than 5.0d-6 hartrees/bohr with B3LYP in a gaussian basis of 6-31G(d,p). Harmonic frequencies are computed for comparison with the infrared spectra measured by attenuated total reflection of a temperature-controlled Ge plate under a layer of cold brine solution. The motivation for this research is to understand the mechanism by which freezing seawater excludes halide ions (mainly Cl super(-)) and why the O-H stretching region of the spectra changes with temperature. Frost flowers, sea ice, and snow in marine environments contain concentrated halides in liquid brine at their surfaces which lead to catalytic destruction of low-altitude ozone in the polar regions of the Earth.
ISSN:1388-0764
1572-896X
DOI:10.1007/s11051-012-0896-3