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铵根离子的动力学行为与生命体内的生物和化学过程密切相关.依据流体力学理论,由于铵根离子与水分子之间存在多个强氢键,其转动应较慢,但实验结果并非如此,其转动的微观机理尚不清晰.本文分子动力学模拟研究表明,水溶液中铵根离子主要以快速、大角度的跳跃方式进行转动,像水分子一样遵从扩展分子跳跃转动模型.通过微观转动模式的分解和两种转动弛豫时间的比较发现,相对其氢键骨架的扩散转动,跳跃转动对其转动速率贡献更大,并随浓度增大不断强化.与水分子氢键交换方式相比,铵根离子更倾向于在非氢键相连的水分子间发生交换.
The kinetic behavior of ammonium ion is closely related to the biological and chemical processes in living body.According to the theory of fluid mechanics, due to the existence of multiple strong hydrogen bonds between ammonium ions and water molecules, the kinetic behavior of ammonium ions should be slow, but the experimental results are not the same , The microscopic mechanism of its rotation is not yet clear.The molecular dynamics simulations in this paper show that the ammonium ions in aqueous solution mainly rotate in a fast and high-angle hopping manner, and follow the molecular hopping and rotation model like water molecules. The comparison of the decomposition and the two rotation relaxation times shows that the jump rotation contributes more to the rotation rate than the hydrogen bond skeleton diffusion diffusion and increases with the increase of concentration.Compared with the hydrogen bond exchange mode, Ammonium ions are more likely to exchange between non-hydrogen bonded water molecules.