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Vibrationally excited iodine I 2 (X,v>20) is an important intermediate in the standard COIL dissociation model. This intermediate is populated by the I* + I 2 (X) reaction. In this model excitation probabilities for the v-th I 2 (X) vibrational level γ(v) are critical parameters. In the present study we examined excitation probabilities γ(v) based on the comparison of calculated populations of vibrational levels of iodine molecules with their experimental values. The total excitation probability for I 2 (X, v>25) was found to be γ(v>25)≈ 0.1. The standard dissociation model with γ(v>25) ≈0.1 cannot provide the observed dissociation rates. Moreover the number of O 2 (a) molecules consumed per dissociated I 2 molecule would exceed 20 if the standard dissociation model is the predominant dissociation pathway, which is at variance with experiment. Barnault et al.3 found that the populations of I 2 (10≤v≤23) were much higher than ν≥30. Such high populations of I 2 (10≤v≤23) could be explained by means of direct excitation in the I* + I 2 (X) reaction. A satisfactory agreement between calculated I 2 (v) populations and the experimental data was achieved for the total excitation probability γ(v>25) =0.05-0.1 and for γ(15 |
