Thermodynamics of Associated Electrolytes in Water: Molecular Dynamics Simulations of Sulfate Solutions
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- 作者：Magali Duvail ; Arnaud Villard ; Thanh-Nghi Nguyen ; Jean-Fran莽ois Dufr锚che
- 刊名：Journal of Physical Chemistry B
- 出版年：2015
- 出版时间：August 27, 2015
- 年：2015
- 卷：119
- 期：34
- 页码：11184-11195
- 全文大小：588K
- ISSN：1520-5207
文摘
A polarizable force field for the sulfate anion SO42鈥?/sup> has been developed and extended from nonpolarizable force fields in order to reproduce its structural and thermodynamics properties in aqueous solution. Two force fields with different atomic partial charges on S and O have been tested and used with molecular dynamics with explicit polarization. The results obtained with our developed force field are in good agreement with the experimental hydration properties of the sulfate anion. In addition to molecular dynamics simulations of the sulfate anion in aqueous solution, potentials of mean force of sulfate electrolytes have been calculated via umbrella-sampling molecular dynamics simulations, i.e., MgSO4, EuSO4+, and UO2SO4. These potentials allow for calculating pair association constants directly comparable to the experimental ones. In the case of monoatomic cations such as Mg2+ and Eu3+, the association constants calculated are in very good agreement with the experimental values, i.e., pKcalc = 2.21 (vs 2.21 experimentally) and 3.86 (vs 3.56鈥?.78 experimentally) for MgSO4 and EuSO4+, respectively. In the case of purely molecular electrolyte (UO2SO4), the association constant calculated (pKcalc = 1.58鈥?.07) is in agreement with the range of values available in the literature (pKexp = 1.17鈥?.14).