Applications of electron spin resonance to gas-phase kinetics.
Applications of electron spin resonance to gas-phase kinetics.
复制标题
电子自旋共振在气相动力学中的应用。
DOI：
10.1126/science.164.3878.381
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发表时间：
1969
期刊：
影响因子：
56.9
通讯作者：
A. A. Westenberg
中科院分区：
文献类型：
--
作者：
A. A. Westenberg
H2+ Br 2 -2 HBr实际上不是通过一个H分子的直接反应发生的，一个Br。得到两个HBr分子。五十年前，人们发现，如果实际发生的化学事件是Br 2 + M，那么关于HBr产生速率的实验数据就可以得到令人满意的解释; 2 Br + M Br+ H2= HBr+ H H+ Br 2 HBr+ Br，其中M是存在的任何物种。不稳定的中间体Br和H是这个简单链机制中的关键成分，处理它们的经典方法是假设它们的浓度与其他物种相比非常小，因此它们的净变化率可以设定为零。这就是所谓的”稳态近似”，它已被应用于化学动力学，但显然是一个托词，可能有效，也可能无效，在一个给定的系统。
H2+ Br2-2 HBr does not actually take place by the direct reaction of one molecule of H., with one of Br. to give two molecules of HBr. Fifty years ago it was shown that experimental data on the rate of HBr production could be interpreted satisfactorily if the actual chemical events occurring wereBr2+ M; 2Br+ M Br+ H2= HBr+ H H+ Br2 HBr+ Br where M is any species present. The labile intermediates Br and H are the key ingredients in this simple chain mechanism, and the classical method of dealing with them is to assume that their concentrations are very small as compared to the other species, so that their net rates of change may be set equal to zero. This is the so-called" steady-state approximation" which has been applied in chemical kinetics but which is clearly a subterfuge that may or may not be valid in a given system.