Results of experiments on dissociation of iodine molecules in the presence of singlet oxygen molecules are presented for wide range of oxygen-iodine media composition. Rate constants values have been obtained: 4.3⋅10-17cm3/s for the reaction O2(1Δ)+O2(1Δ)→O2(1Σ) +О2(3Σ) − (1), 2.8⋅10-13 cm3/s for the reactionO2(1Δ)+I(2P1/2)→O2(1Σ)+I(2P3/2) − (4) and 8.3⋅10-11 cm3/s for the reaction O2(1Σ) +I2→О2(3Σ)+2I − (2). Analysis of experiments shows that for the wide range of oxygen-iodine medium composition the dissociation occurs via the chain of reactions (1), (2), O2(1Δ)+I(2P3/2)→О2(3Σ)+I(2P1/2), (4) and via cascade process I2+I(2P1/2)→I2(v)+I(2P3/2), I2(v)+O2(1Δ)→2I+О2(3Σ). Contributions of each mechanism in the dissociation of the iodine are comparable for the typical composition of the active medium of the supersonic chemical oxygen-iodine laser. The experiments did not reveal the contribution of vibrationally excited oxygen molecules in the dissociation of iodine. Thus, the experiments and the following conclusions are fully confirmed iodine dissociation mechanism previously proposed by Heidner et al. (J. Phys. Chem., 87, 2348 (1983)).
A novel optical pumping scheme considering a two-step irradiation by light at wavelengths near 500 nm and 1315 nm is proposed in this work. Radiation at 500 nm is used to dissociate about 1% of iodine molecules. The radiation at 1315 nm excites atomic iodine to the 2P1/2 state. Singlet oxygen molecules are produced via the energy exchange process I(2P1/2)+O2(X3Σ)→ I(2P3/2)+O2(a1Δ), while I(2P1/2)+O2(a1Δ) energy pooling produces b1Σ oxygen. I(2P3/2) and O2(1Σ) then accelerate the dissociation of I2. After gas dynamic cooling in supersonic nozzle, active medium may reach ~100 W cm–2 and small signal gain of ~0.01 cm-1.
KEYWORDS: Oxygen, Iodine, Molecules, iodine lasers, Chemical lasers, Gas lasers, Optical pumping, Chemical species, Active optics, Chemical oxygen iodine lasers, Laser optics, Semiconductor lasers, Aerospace engineering, Laser systems engineering
The kinetics of the processes in an O2/I2/Ar/H2O gas flow that is irradiated simultaneously by light at wavelengths near 500 nm and 1315 nm, is considered. Radiation at 500 nm is used to photodissociate about 1% of the iodine molecules. The radiation at 1315 nm excites atomic iodine to the 2P1/2 state. Singlet oxygen molecules are produced via the energy exchange process I(2P1/2)+O2(X3Σ) → I(2P3/2) + O2(a1Δ), while I(2P1/2)+O2(a1Δ) energy pooling produces b1Σ oxygen. I(2P1/2) and O2(b1Σ) then accelerate the dissociation of I2. This active medium may reach ~40 W/cm–2 at an optical efficiency of 50%.
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