Primary Process in the Photolysis of Alkyl Iodides

Abstract

RECENTLY, Kasper and Pimental¹ have detected stimulated emission from the transition I(5p²P_½) → I(5p²P_3/2) + hν (1.315µ) resulting from the flash photodissociation of methyl and trifluoromethyl iodides. This provided the first direct observation of electronically excited iodine atoms produced from the photolysis of alkyl iodides. A spectral analysis of methyl iodide by Porret and Goodeve² had previously indicated that I(5²P_½) should be predominantly produced on the photolysis of this compound. Furthermore, these authors pointed out the close similarity between the spectra of the lower aliphatic iodides. The work described in this communication, which utilized kinetic spectroscopy in the vacuum ultra-violet region of the spectrum, confirms the work of Kasper and Pimental and extends the observations to ethyl, propyl and butyl iodides. Preliminary observations on the photolysis of hydrogen iodide are also reported here.