Oxygen assisted iodine atoms production in an RF discharge

Experiments and modeling of CH3I dissociation in the plasma generated by a 40 MHz RF discharge were performed. A discharge chamber of an original design, consisting of quartz tubes between two planar electrodes, permitted the production of iodine atoms with number densities up to 2×1016 cm-3. In this discharge chamber, contamination of the walls of the tubes did not hinder discharge stability, providing a good iodine production rate. Addition of oxygen into Ar:CH3I mixture resulted in a substantial increase in iodine extraction efficiency. When the discharge power reached 200 W, complete CH3I dissociation in a Ar:CH3I:O2 mixture was observed. The fraction of discharge power spent on iodine atom production at a 0.17 mmol/s CH3I flow rate was 16%.