Kinetic pathways of ion pair dissociation in water
Kinetic pathways of ion pair dissociation in water
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DOI：
10.1021/jp984837g
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发表时间：
1999-05-06
影响因子：
3.3
通讯作者：
Chandler, D
中科院分区：
文献类型：
--
作者：
Geissler, PL;Dellago, C;Chandler, D
我们成功地将跃迁路径抽样方法应用于具有长程相互作用的多体系统的确定性动力学。我们调查的过程中，在水中的模型Na+ Cl-离子对的解离，涉及到广泛的过渡途径，集体溶剂运动发挥了重要作用。过渡态沿着这些途径涵盖了广泛分布的离子分离。接触中的离子对保持相关的平均约20 ps，时间尺度大大长于过渡态理论与离子分离作为序参量预测的约3 ps。在相反的摩擦效应（有或没有记忆）的基础上的障碍交叉理论，我们发现，这些时间尺度之间的差异来自被忽视的溶剂自由能障碍，而不是随机的离子对的抖振。
We have successfully applied the transition path sampling method to the deterministic dynamics of a many-body system with long-ranged interactions. The process we investigate, dissociation of a model Na+CI- ion pair in water, involves a wide range of transition pathways in which collective solvent motions play an important role. Transition states along these pathways encompass a broad distribution of ionic separations. Ion pairs in contact remain associated for similar to 20 ps on average, a time scale considerably longer than the similar to 3ps predicted by transition state theory with ionic separation as the order parameter. In contrast to theories of barrier crossing based upon frictional effects (with or without memory), we find that the discrepancy between these time scales arises from neglected solvent free energy barriers rather than stochastic buffeting of the ion pair.