Polarization Behavior of Water in Extreme Aqueous Environments: A molecular dynamics study based on the Gaussian Charge Polarizable Water Model.
- ORNL
We study the polarization behavior of water under geologically-relevantextreme aqueous environments along four equidistant supercriticalisotherms, 773 ! T (K) ! 1373, and over a wide pressure range,0 < P(GPa) ! 30 , by isobaric-isothermal molecular dynamics simulationsof the Gaussian Charge Polarizable (GCP ) water model, to unravel anddiscuss the underlying link between two precisely defined orientationalorder parameters and the magnitude of the average induced dipole momentof water. The predicted behavior indicates an isothermal linear dependence(a) between the magnitude of the average induced dipole moment μind andthe average system density ! , (b) between the magnitude of the averageinduced dipole μind and that of the total dipole μtot , resulting from (c) acompensating (inverse) dependence between the permanent-to-induceddipolar angle ! and the magnitude of the average induced dipole momentμind . Moreover, we interpret this behavior in terms of the evolution of thestate dependent tetrahedral order parameter qT and the correspondingbond-order parameter Q6 , supplemented by the microstructural analysisbased on the three site-site radial distribution functions of water and thedistance-ranked nearest-neighbors distributions. Finally, we show thatwhile water exhibits a dramatic microstructural transformation from anopen four-coordinated hydrogen-bonded network at normal conditions to a quasi close-packed coordination, it still preserves a significant degree of hydrogen bonding.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 985773
- Journal Information:
- Journal of Chemical Physics, Vol. 133, Issue 7; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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