Atomic iodine generation via F atoms for COIL

Abstract

Chemical generation of atomic iodine for a Chemical Oxygen-Iodine Laser (COIL) was investigated experimentally. This all-gas process includes atomic fluorine as an intermediate species. In the two-step reaction mechanism, F atoms are produced in reaction of molecular fluorine with NO and react further with hydrogen iodide to iodine atoms. The efficiency of this process was studied in dependence on mixing conditions, flow rate of reacting gases and pressure in the reactor. The maximum concentration of atomic iodine was obtained at approximately equimolar ratio of reacting gases (F 2 , NO and HI), which agrees with the stoichiometry of the production reactions. A shortage of any of the reacting gases limits the rate of atomic iodine formation. A considerable excess of F 2 against NO at a simultaneous deficit of HI had a most detrimental effect on atomic iodine production. Sufficiently high concentrations of atomic iodine (5 to 8 x 10 15 cm -3 ) can be achieved by this method even at pressure 4 - 9 kPa that enable to inject the gas with iodine atoms into the singlet oxygen flow upstream the nozzle throat in the chemical oxygen-iodine laser.