Study of rotational temperature of oxygen DC glow discharge in Silica and Pyrex discharge tubes

Abstract

Active DC glow discharges in oxygen have been studied in Silica and Pyrex discharge tubes for medium pressures up to 550 Pa and for discharge currents up to 40 mA. Electric field strength measured by a double-probe technique was found to increase with the pressure and to decrease with the discharge current, which is typical for DC glow discharges. We have focused on the emitted radiation. The rotational temperature ( T rot) of molecular oxygen was determined from the PP and PQ branches of the well-resolved atmospheric A-band of molecular oxygen at 760 nm. Good agreement between values of T rot obtained from particular branches was found. The increase of the rotational temperature with increasing pressure and discharge current has been observed in both discharge tubes, however, the values of rotational temperature were systematically higher in the tube made of Pyrex glass. This difference was explained by the particular thermal conductivity of the tube material.