The total quenching rate constants of argon atoms in the 4p′[1/2]0, 4p[1/2]0, 4p[3/2]2, and 4p[5/2]2 states (2p1, 2p5, 2p6, and 2p8, respectively, in the Paschen numbering system) by rare gases, H2, D2, N2, CO, NO, O2, F2, Cl2, CO2, NO2, CH4, C2H2, C2H4, C2H6, CF4, CHF3, and SF6 have been determined at room temperature. These four excited states of argon (energy 13.09–13.48 eV) were selectively prepared by two-photon excitation from the ground state using VUV (184–190 nm range) laser pulses. The total quenching rates were deduced from the pressure dependence of the decay times of the excited-state atoms, measured by observing their fluorescence emission intensities in the presence of added reagents. The quenching constants increase from values of ≅0.01×10−10 cm3 atom−1 s−1 for Ne, to ≅0.1×10−10 cm3 atom−1 s−1 for He and Ar, and to very large values, (5–15)×10−10 cm3 atom−1 s−1, for most polyatomic molecules, F2, Cl2, and O2. The quenching mechanisms of the Ar(4p,4p′) atoms are briefly discussed and compared to the reactions of the Ar(4s,4s′) metastable and resonance state atoms, 11.55–11.83 eV, which can serve as a reference.

In an asymmetric capacitively coupled radio-frequency (cc-RF) CF 4 plasma, the radical densities of CF and CF 2 were measured using laser-induced fluorescence spectroscopy. From the spatially (along the symmetry axis) and temporally (after switching off the discharge) resolved data, the source distribution and the sticking coefficients are inferred. We present results for three different electrode materials (stainless steel, aluminium and silicon). According to our data, the strength and the position of the sources depend strongly on the electrode material and the applied voltage. While the CF-sources are in the sheath in front of the powered electrode for stainless steel, they are on the surface of the powered electrode in the case of aluminium. By using a simple diffusion model for the analysis of the afterglow data, it can be shown that CF 2 is destroyed exclusively at the walls and the decay time is determined by diffusion and sticking only. In contrast, for CF, surface as well as volume losses due to chemical reactions are important.

The quenching rate of the 750.4 nm actinometer line in argon by H2 and several hydrocarbons (CH4, C2H2, C2H4, C2H6) has been determined. Argon atoms at room temperature are excited by two-photon excitation at 184 nm to the 4p′[1/2]0 state, and the decay time of the fluorescence emission at 750.4 nm is measured. The quenching rates are inferred from the change of the decay time with the pressure of the quenching gas. For hydrocarbons, the quenching rates are of the order of 10−9 cm3 s−1. The radiative lifetime of the 4p′[1/2]0 is found to be 24 ns.

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