Mechanism of dark decomposition of iodine donor in the active medium of a pulsed chemical oxygen — iodine laser

Abstract

A scheme is proposed that describes the dark decomposition of iodide — the donor of iodine — and the relaxation of singlet oxygen in the chlorine-containing active medium of a pulsed chemical oxygen — iodine laser (COIL). For typical compositions of the active media of pulsed COILs utilising CH3I molecules as iodine donors, a branching chain reaction of the CH3I decomposition accompanied by the efficient dissipation of singlet oxygen is shown to develop even at the stage of filling the active volume. In the active media with CF3I as the donor, a similar chain reaction is retarded due to the decay of CF3 radicals upon recombination with oxygen. The validity of this mechanism is confirmed by a rather good agreement between the results of calculations and the available experimental data. The chain decomposition of alkyliodides accompanied by an avalanche production of iodine atoms represents a new way of efficient chemical production of iodine for a COIL.