Use of optical emission spectroscopy for determining the number concentration of chlorine atoms in a chlorine-oxygen plasma

Applicability of the emission spectroscopy technique in calculating the con centration of chlorine atoms in a chlorine-oxygen plasma was shown by compa ring experimental and calculated relative intensities of the 452.62-nm chlo rine line (5P(2)p(3/2)(0) --> 4s(2)p(3/2) transition, excitation potential E = 11.94 eV). The number concentration of chlorine atoms found by calibrat ion with pure gases using this emission line was compared with the one meas ured by absorption spectroscopy. Some discrepancy between the results at an oxygen content greater than 50% in the mixture is due to the presence of o xygen compounds of chlorine which are detected as chlorine atoms by the abs orption spectroscopy.