Rotational temperature of oxygen molecules in DC glow discharge in O _2-Ar mixtures sustained in discharge tube made from Pyrex glass

摘要

The active DC glow discharge sustained in pure O_2 and O _2-Ar mixtures with Ar/O_2 concentration ratios up to 50% has been studied in a Pyrex discharge tube for pressures up to 500 Pa and for discharge currents up to 40 mA. The electric field strength and emission spectra parameters of the discharge were studied by means of the double-probe method and optical emission spectroscopy. The electric field strength was found to increase with the pressure and decrease with the discharge current, which is typical for DC glow discharges. Considering O_2-Ar mixtures, the values of electric field strength decreased with Ar/O_2 ratio. We have focused on the emitted radiation. The rotational temperature Trot of molecular oxygen was determined from the well-resolved atmospheric A-band at 760 nm. The increase of the rotational temperature with increasing deposited power has been observed for all studied Ar/O_2 ratios. Moreover, it has been found that values of Trot are independent of the mixture composition.