Mechanism and kinetics of iodine dissociation in COIL

摘要

Dissociation of I_2 by O_2(a~1Δ), with subsequent excitation of I~*, was first observed by Arnold et al.~1 in 1966. This key discovery led to the eventual development of the chemical oxygen iodine laser (COIL). The mechanism by which I_2 is dissociated was not determined by Arnold et al.~1 and has remained elusive, despite many experimental attempts to unravel this question. Although the details are not known, it is apparent that a complex interplay between vibrationally and electronically excited states of I_2 is involved. Vibrationally excited states of O_2 have also been implicated. Characterization of the dissociation process is an important issue for COIL as the efficiency is impacted by the energy cost of dissociating the iodine. In this paper we provide a historical summary of work on the dissociation mechanism, and summarize the current understanding of the problem.