Picosecond time-resolved resonance Raman study of CH2I-I produced after ultraviolet photolysis of CH2I2in CH3OH, CH3CN/H2O and CH3OH/H2O solutions

Wai Ming Kwok, Chensheng Ma, Anthony W. Parker, David Phillips, Michael Towrie, Pavel Matousek, David Lee Phillips

Research output: Journal article publicationJournal articleAcademic researchpeer-review

24 Citations (Scopus)


We present picosecond time-resolved resonance Raman spectroscopy experiments investigating the photo-products produced after ultraviolet photolysis of CH2I2in CH3OH solution and in 50% CH3OH/50% H2O and 50% CH3CN/50% H2O by volume mixed solvents. We observe that isodiiodomethane (CH2I-I) is formed within several picoseconds and has a lifetime that significantly depends on the solvent system (time constant of 3.8 ns in CH3OH, 1.8 ns in 50% CH3CN/50% H2O, and 0.8 ns in 50% CH3OH/50% H2O). Our results indicate that CH2I-I can be formed via geminate recombination in aqueous environments but will have a shorter lifetime than in previous experiments done in several organic solvents. The variations in the lifetime of CH2I-I in the presence of H2O and CH3OH could be due to its chemical reaction with the O-H bond and/or possibly faster cleavage of the weak I-I bond in aqueous solutions. We briefly discuss the potential role of CH2I-I in the release of reactive halogens in aqueous environments.
Original languageEnglish
Pages (from-to)2624-2628
Number of pages5
JournalJournal of Physical Chemistry A
Issue number15
Publication statusPublished - 17 Apr 2003
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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