On the photochemistry of aqueous solutions of chloride, bromide, and iodide ions

Joshua Jortner*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The photochemistry of aqueous solutions of Cl-, Br-, I- and OH- was investigated at 2537, 2288, and 1849 Å., in the temperature range 5-37°. The excited halide ions dissociate into a halogen atom and a solvated electron. Scavengers for solvated electrons, such as H3O+, N2O, or acetone compete with the secondary diffusive recombination of these but do not interact with the spectroscopic excited state. Cl atoms dehydrogenate ethanol and methanol, while I atoms appear to be unable to do so at all wave lengths. For Br atoms, however, the results indicate that at 2288 Å., formed in their lower energy 2P3/2, state, they do not dehydrogenate the scavengers but may be able to do so when formed in the higher energy 2P1/2 state at 1849 Å. The effects of temperature, wave length, added salt, and type of halide ion indicate that the atom-electron pair is formed from the excited ion in a distinct step. This process, essentially one of charge asymmetrization, competes with the deactivation of the excited ion. The value of the limiting constant quantum yield, T, obtained at high scavenger concentrations depends on this competition.

Original languageEnglish
Pages (from-to)247-255
Number of pages9
JournalJournal of Physical Chemistry
Volume68
Issue number2
DOIs
StatePublished - 1964
Externally publishedYes

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