Time-resolved k(E-*) measurements for dissociation of allyl iodide vibrationally excited via C-H overtones (v=6)

The direct time-resolved measurements of the energy dependent rate constant k(E*) have been carried out for dissociation of allyl iodide (AI) vibratio nally excited via C-H overtones (v=6). Resonant two-photon ionization (R2PI ) technique has been used for the detection of atomic iodine I(P-2(3/2)) ar ising from the dissociation of photoexcited AI molecules. For R2PI detectio n a method with narrow-band vacuum ultraviolet radiation (VUV) was used. VU V radiation was generated by means of nonresonant frequency tripling of vis ible dye-laser radiation in gaseous xenon. Measured k(E-*) values were foun d to be in excellent agreement with those calculated within the microcanoni cal version of the statistical Rice-Ramsperger-Kassel-Marcus theory in its "phase space" or "loose" transition state limit. The canonical version of t he same model is also in good agreement with experimental data from the lit erature on the dissociation of allyl iodide under thermal heating condition s where collisional excitation takes place. (C) 2000 American Institute of Physics. [S0021-9606(00)01714-1].