Detection of NH₂ Radical in Ammonia Radio-Frequency Plasmas by Laser-Induced Resonance Fluorescence

By means of one photon absorption laser-induced resonance fluorescence at 599.5 nm the relative concentrations of amidogen (NH₂) radical in the ammonia (NH₃) radio-frequency (rf) plasma source were measured under different discharge pressures and rf powers. The time dependence of the fluorescence which comes from the radiation 1₀₁ -2₁₁ of the P-branches of the Σ vibronic sub-bands can be described by a single-exponential decay. The decay time of NH₂(A²A₁) Σ (0, 9, 0) rovibronic state was determined. The spatial dependence of the NH₂ density in discharge tube was measured.