| Cite this article as: Qiao Meng-Dan,Li Fei,Wang Mei-Ling,Zhu Han-Yu,Zhang Yu,Yuan Jun-Sheng. Application of molecular dynamics simulation and Raman spectroscopy to study the hydration phenomena of calcium, magnesium and chloride ions [J]. J. At. Mol. Phys.(原子与分子物理学报), 2023, 40: 011003 (in Chinese) |
| Application of molecular dynamics simulation and Raman spectroscopy to study the hydration phenomena of calcium, magnesium and chloride ions |
| Hits 541 Download times 182 Received:August 11, 2021 Revised:September 28, 2021 |
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| Key Words
Calcium Magnesium Chlorine Ionic hydration Molecular dynamics simulation Raman spectroscopy |
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| Abstract
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| Using molecular dynamics method, the hydration phenomenon of Ca2+, Mg2+, Cl- in an aqueous solution with a density of 1.0g/cm3 at 298 K was simulated, and the microscopic distribution of water molecules around the corresponding ions was obtained. It was found that around calcium ions, water molecules approached the central ion by oxygen ions; around chloride ions, water molecules approached the central ion by the hydrogen atoms. By analyzing the radial distribution function, coordination number curve, hydration number, and hydration radius, it was found that the hydration number and hydration radius of Ca2+ were greater than those of Mg2+. Therefore, it was speculated that the hydration capacity of Ca2+ was stronger than that of Mg2+. In order to simulate the real aqueous system, the microstructure of CaCl2 aqueous solutions at different concentrations were studied by molecular dynamics and Raman spectroscopy. Molecular dynamics studies found that with the increase of concentration, the coordination number of Ca2+ and Cl- in CaCl2 solution showed a decreasing trend. At the same time, as the concentration increases, the self-diffusion coefficients of Ca2+ and Cl- also showed a decreasing trend. This may be caused by the microscopic reverse motion of the ions. The Raman results showed that with the increase of CaCl2 concentration, the hydrogen bond network structure in the solution was damaged severely. And there appeared more contact ion pairs formed by Ca2+ and Cl-. |
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