Detection of atomic oxygen: Improvement of actinometry and comparison withlaser spectroscopy

The density of atomic oxygen in an oxygen rf discharge in the Gaseous Elect ronics Conference reference cell is determined from the intensity ratios of the argon lambda = 750 nm line (2p(1)- 1s(2)). and the atomic oxygen lines lambda = 777 nm (P-5-S-5) and lambda = 844 nm (P-3-S-3). Laser induced flu orescence spectroscopy with two-photon excitation is applied to the oxygen plasma, and the results of both methods are compared. The improved actinome try is based on the calculation of electronic collisional excitation of the upper levels of these transitions. The required information on the electro n energy distribution function is obtained from a model calculation of the discharge. Good agreement of the results are obtained, if excitations via d issociative channels and also quenching rates are accounted for. (C) 2000 A merican Institute of Physics. [S0021-8979(00)03422-8].