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Author Demmel, F. ♦ Mukhopadhyay, S.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ COMPUTERIZED SIMULATION ♦ CORRELATIONS ♦ DIFFUSION ♦ EINSTEIN FIELD EQUATIONS ♦ FLUORINE ♦ MOLECULAR DYNAMICS METHOD ♦ NEUTRON DIFFRACTION ♦ QUASI-ELASTIC SCATTERING ♦ SODIUM ♦ SODIUM FLUORIDES ♦ SODIUM IONS ♦ STOCHASTIC PROCESSES ♦ VELOCITY
Abstract The ionic stochastic motions in the molten alkali halide NaF are investigated by quasielastic neutron scattering and first principles molecular dynamics simulation. Quasielastic neutron scattering was employed to extract the diffusion behavior of the sodium ions in the melt. An extensive first principles based simulation on a box of up to 512 particles has been performed to complement the experimental data. From that large box, a smaller 64-particle box has then been simulated over a runtime of 60 ps. A good agreement between calculated and neutron data on the level of spectral shape has been obtained. The obtained sodium diffusion coefficients agree very well. The simulation predicts a fluorine diffusion coefficient similar to the sodium one. Applying the Nernst-Einstein equation, a remarkable large cross correlation between both ions can be deduced. The velocity cross correlations demonstrate a positive correlation between the ions over a period of 0.1 ps. That strong correlation is evidence that the unlike ions do not move completely statistically independent and have a strong association over a short period of time.
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-01-07
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 144
Issue Number 1


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