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On the Recombination Rate of Iodine Atoms in the Presence of Various Gases


Engleman, Rolf (1959) On the Recombination Rate of Iodine Atoms in the Presence of Various Gases. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/KAVE-WG75.


The rate of iodine atom recombination in the presence of various gases has been studied by the flash photolysis technique. The temperature dependence of the rate constant has been determined for recombination in helium, hydrogen, benzene, and methyl iodide. The negative temperature dependences are fitted by the form, k∝1/Tn, where n(He) = 0.80, n(H2 = 1.48, n(C6H6 = 2.53, and n(CH3I = 3.24.

The iodine atom recombination rate constant was also measured at 50°C. for ethyl iodide, hydrogen iodide, carbon monoxide, and nitric oxide. The rate constants relative to helium at 50°C. are:

He      1.00       C2H5I    179.
H2       3.33       NI         21.1
C6H6   61.1       CO       4.07
CH3I    88.8       NO       >1.4 x 104

Nitric oxide appears to be a very efficient third body gas and only a lower limit on the rate constant could be established.

Calculations have been made for some possible mechanisms of iodine atom recombination. A classical three body collision model is proposed for atom recombinations. The classical equations of motion were programmed to be solved numerically on a digital computer and some trajectories were examined.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Chemistry and Physics)
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Minor Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Davidson, Norman R.
Thesis Committee:
  • Wulf, Oliver Reynolds (chair)
  • Buchman, Edwin R.
  • Davidson, Norman R.
  • Lauritsen, Thomas
  • Mazo, Robert Marc
Defense Date:1 January 1959
Non-Caltech Author Email:engleman (AT)
Errata:Page 25. Equation (18): Exponent given as ( 4.09±.03) should be (8.68±.01). Page 25. Line 13 from top: 500K. should be 500C. Page 79. Reference 7: Author omitted after Norrish; insert A. J. Harrison.
Record Number:CaltechETD:etd-02062006-102644
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:517
Deposited By: Imported from ETD-db
Deposited On:06 Feb 2006
Last Modified:18 Oct 2023 19:04

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