MODELS RELATING MOLECULAR REACTIVITY AND DIFFUSION IN LIQUIDS
MODELS RELATING MOLECULAR REACTIVITY AND DIFFUSION IN LIQUIDS
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DOI：
10.1021/ja01602a007
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发表时间：
1956
影响因子：
15
通讯作者：
R. M. Noyes
中科院分区：
文献类型：
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作者：
R. M. Noyes
建立了孤立的一对分子相互反应的趋势与相对扩散位移的频率和大小有关的模型。虽然大多数实验测试显示出很小的区分性，但从清道夫浓度对光化学解离量子产额的影响可以估计扩散运动的个别参数。现有的数据表明，液体中的扩散包括几乎连续的运动和小的单个位移，而不涉及分子直径量级的跳跃，而分子的扩散运动涉及许多高频的小距离随机位移，但从实验测量得到的大多数量只需要宏观扩散系数，而不依赖于微观参数。因此，它们没有区分液体中的扩散模型，在该模型中，分子直径数量级的位移被势垒所反对，而在另一种模型中，更频繁但更短的位移被低得多的势垒所反对。1此外，由于伴随着液体的热膨胀，在恒压下测量的温度系数不能提供关于屏障高度的直接信息。
Models are developed by which the tendency of an isolated pair of molecules to react with each other is related to the frequency and magnitude of relative diffusive displacements. Although most experimental tests will show littlediscrimination, the individual parameters of diffusive motion can be estimated from the effect of scavenger concentration on quantum yield of photochemical dissociation. Data currently available suggest thatdiffusion in liquids involves almost continuous motion and small individual displacements, and does not involve “jumps” of the order of a molecular diameter that are opposed by significant potentialbarriers.Although diffusive motion of molecules involves many random displacements for small distancesat high frequency, most quantities calculable from ex-perimental measurement require only the macro-scopic diffusion coefficient and do not depend on the microscopic parameters. Therefore, they do not distinguish between a model of diffusion in liquids in which displacements of the order of a molecular diameter are opposed by a potential barrier, and another model in which more frequent but shorterdisplacements are opposed by a very much lower barrier. 1 Moreover, temperature co-efficients measured at constant pressure do not yield direct information on barrier heights because of the accompanying thermal expansion of the liquid.