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This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.The Recombination of Atoms. II. Causes of Variation in the Observed Rate Constant for Iodine Atoms
Margaret I. Christie, Anna J. Harrison, R. G. W. Norrish and G. Porter
Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences
Vol. 231, No. 1187 (Sep. 20, 1955), pp. 446457
Published by: Royal Society
Stable URL: http://www.jstor.org/stable/99799
Page Count: 12
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Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Abstract
A reinvestigation of the recombination of iodine atoms in presence of the inert gases over a wider range of experimental conditions has shown that the simple termolecular rate law d(I)/dt = k(I)2 (M) is not obeyed. For each of the inert gases k, the experimentally determined termolecular rate constant, increases with the ratio (I2)/(M), where (I2) and (M) are the concentrations of iodine molecules and inert gas molecules respectively. The dependence of k on (I2)/(M) was obscured in previous work by the fact that a thermal effect, which results in a lowering of the apparent value of k as recombination proceeds, increases as (I2)/(M) increases and compensated for the real increase in k with (I2)/(M). Except at low (I2)/(M) values, k is a linear function of (I2)/(M), the gradient being the same for all five inert gases. A rapid termolecular reaction I+I+I2 = I2+I2 with a rate constant k = 470 × 1032 ml.2 mol.2 s1 is postulated to explain the linear relationships. By extrapolation the values of kM the thirdorder rate constants for the five inert gases are $ \matrix\format\c\kern.8em&\c\kern.8em&\c\kern.8em&\c\kern.8em&\c\kern.8em&\ c \\ M & \text{He} & \text{Ne} & \text{A} & \text{Kr} & \text{Xe} \\ 10^{32}k_{M}(\text{ml}.^{2}\text{mol}.^{2}\text{s}^{1}) & 0\cdot 67 & 0\cdot 92 & 1\cdot 84 & 2\cdot 25 & 2\cdot 99 \endmatrix$
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Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences © 1955 Royal Society