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Article
Characterization of Iso -Cf2 I2 in Frequency and Ultrafast Time Domains
Journal of Chemical Physics
  • Alexander N Tarnovsky, Bowling Green State University
  • Patrick Z. El-Khoury
  • Lisa George
  • Aimable Kalume
  • Scott A. Reid
  • Bruce S. Ault
Document Type
Article
Disciplines
Abstract

The photolysis of diiododifluoromethane (CF2 I2) in condensed phases was studied by a combination of matrix isolation and ultrafast time-resolved spectroscopy, in concert with ab initio calculations. Photolysis at wavelengths of 355 or 266 nm of CF2 I2:Ar samples (1:5000) held at ∼8 K yielded iso -CF2 I2 (F2 C-I-I), a metastable isomer of CF2 I2, characterized here for the first time. The infrared (IR) spectra of this isomer were recorded in matrix experiments, and the derived positions of the C-F stretching modes are in very good agreement with the predictions of high level ab initio calculations, which show that the iso -form is a minimum on the CF2 I2 ground state potential energy surface. The formation of this isomer following 350 nm excitation of CF2 I 2 in room temperature CCl4 solutions was monitored through its intense C-F stretching mode by means of ultrafast time-resolved IR absorption. Together, matrix isolation and ultrafast IR absorption experiments suggest that the formation of iso -CF2 I2 occurs via recombination of CF2 I radical and I atom. Ultrafast IR experiments detect a delayed rise of iso -CF2 I-I absorption, placing an upper limit of 400 fs for the C-I bond dissociation and primary geminate recombination processes. The product absorption spectrum recorded 1 ns after 350 nm excitation of CF2 I2 in solution is virtually identical to the visible absorption spectrum of i so -CF2 I2 trapped in matrix isolation experiments [with subtracted I2 (X) absorption]. The formation of this isomer in solution at room temperature has direct dynamic implications for the ultrafast production of molecular iodine from electronically excited CF 2 I2. © 2010 American Institute of Physics.

Publication Date
1-1-2010
Publisher
American Institute of Physics
DOI
https://doi.org/10.1063/1.3357728
Citation Information
Alexander N Tarnovsky, Patrick Z. El-Khoury, Lisa George, Aimable Kalume, et al.. "Characterization of Iso -Cf2 I2 in Frequency and Ultrafast Time Domains" Journal of Chemical Physics (2010)
Available at: http://works.bepress.com/alexander_tarnovsky/3/