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在 L i Br与水的物质量比分别为 1∶ 64、1∶ 32、1∶ 16、1∶ 8、1∶ 4和 1∶ 3的情况下 ,对 L i Br溶液从低温到高温的分子动力学模拟进行了研究。随浓度增加 ,锂离子的水合数量呈减少趋势但同时又从 L i+- Br-接触离子对的数量增加中得到补偿 ,而 L i离子的第一配位壳层的配位数量保持不变。在高浓度 Li Br溶液中 ,Br- O之间的距离有所增加 ,Br-- O的径向分布的形状更趋于非对称 ,从而很好地确定了 Br离子水合壳层 L i+- Br-接触离子对可以在更稀的溶液中产生 ,但随浓度增加而增加。L i+- Br-距离明显短于溶液中 Li离子与 Br离子的离子半径之和 ,也短于 L i Br晶体中两者离子半径之和。高浓度溶液中水分子的结构几乎被破坏 ,水分子间的氢键明显增加 ,但没有消失。对 L i+、Br-和水的扩数系数计算值与实验值进行了比较
In the case where the mass ratio of L i Br to water is 1:64, 1:32, 1:16, 1: 8, 1: 4, and 1: 3, respectively, molecules of L i Br solution from low temperature to high temperature Dynamic simulation was studied. As the concentration increases, the hydration number of lithium ions decreases, but at the same time it is compensated by the increase of the number of L i + - Br - contact ions, while the coordination number of the first coordination shell of L i remains the same. In the high concentration Li Br solution, the distance between Br-O increases and the shape of Br-O radial distribution tends to be asymmetric, so that the Br ion hydrated shell L i + -Br - Contact ion pairs can be produced in more dilute solutions, but increase with increasing concentration. The L i + - Br - distance is significantly shorter than the sum of the ion radii of Li ions and Br ions in the solution and also shorter than the sum of the ion radii of the two ions in the L i Br crystal. The structure of water molecules in high concentration solution is almost destroyed, and the hydrogen bond between water molecules obviously increases, but it does not disappear. The calculated values of the expansion coefficients of L i +, Br- and water are compared with the experimental values