Studies Of Singlet Delta Oxygen Generator By Electric Discharge

Great success has been obtained in the research and development of achemical oxygen-iodine laser(COIL) over the last 20 years. The excited specieswhich transfer its energy to iodine atom, in COIL, singlet delta oxygen(SDO), isobtained in a chemical generator through the following chemical reaction in liquidphase: Cl₂ + 2KOH + H₂O₂ →2KCl + 2H₂O + O₂(1^{â–³}g ) . H₂O generated by thereaction in SDO gas is a strong quencher of excited atomic iodine, which put alimit for the application of COIL. A new method of SDO production is needed toallow oxygen-iodine laser. SDO can be produced in electric discharge. Theadvantages of such a method are the absence of H₂O, the feasibility of adevelopment of an all gas phase oxygen-iodine laser.In this paper, RF oxygen plasma was studied experimentally, moreover, theelectric simulation based on the chemical reaction of oxygen plasma wascomputed.Through a series experiments, some benefit conclusions were obtained. Thetotal pressure was from 200Pa to 400Pa, the flow rate was from 0.5 to 2.0 SLM.The SDO yield was decreasing with gas pressure increasing and increasing withRF power increasing. The relationship of the yield and the flow rate was notmonotonous and exhibited an optimum. In such cases, the SDO yield up to 10.6±2.2% was achieved. When the mixtures of oxygen with Argon or Helium wereused, the SDO yield was increasing strongly. The optimum yield up to 14% wasobtained.The model of plasma chemistry was developed to predict the appropriateelectron mean energy and flow rate and discharge pressure for the generation ofsinglet oxygen molecule, based on physical chemistry with a simple reactionmodel. The model included the collisions of atom with molecule and electron withother species. It was found that electron mean energy must be less than 2.5eV. Anoptimum electron density should be 1×10¹²Ã¯Â½Å¾1×10¹³molecules/cm³. Dischargepressure played the second role among the parameters.