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The total quenching rate constants of argon atoms in the 4p[sup ′][1/2][sub 0], 4p[1/2][sub 0], 4p[3/2][sub 2], and 4p[5/2][sub 2] states (2p[sub 1], 2p[sub 5], 2p[sub 6], and 2p[sub 8], respectively, in the Paschen numbering system) by rare gases, H[sub 2], D[sub 2], N[sub 2], CO, NO, O[sub 2], F[sub 2], Cl[sub 2], CO[sub 2], NO[sub 2], CH[sub 4], C[sub 2]H[sub 2], C[sub 2]H[sub 4], C[sub 2]H[sub 6], CF[sub 4], CHF[sub 3], and SF[sub 6] 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[sup -10] cm[sup 3] atom[sup -1] s[sup -1] for Ne, to ≅0.1×10[sup -10] cm[sup 3] atom[sup -1] s[sup -1] for He and Ar, and to very large values, (5–15)×10[sup -10] cm[sup 3] atom[sup -1] s[sup -1], for most polyatomic molecules, F[sub 2], Cl[sub 2], and O[sub 2]. The quenching mechanisms of the Ar(4p,4p[sup ′]) atoms are briefly discussed and compared to the reactions of the Ar(4s,4s[sup ′]) metastable and resonance state atoms, 11.55–11.83 eV, which can serve as a reference. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Optical pumping has been used to select Ar atoms in the metastable 3P2 or 3P0 state in a flowing afterglow reactor. The relative concentrations of the two metastable states were assigned from observation of the N2(C,v’) emission spectra. The isolated reactions of the Ar(3P2) and Ar(3P0) atoms with F2, NF3, Cl2, CCl4, PCl3, and SOCl2 were examined at 300 K by observation of ArCl* and ArF* formation. The total quenching rate constants for Ar(3P0) are slightly larger than for Ar(3P2). The Ar(3P2) atom reactions give only the B and C states of ArF* and ArCl*; the Ar(3P0) atom reactions give a mixture of B, C, and D states with B and D being favored. Thus, a propensity for conservation of the Ar+ ion–core configuration was found. The branching fraction for ArX* formation from Ar(3P0) with Cl2, SOCl2, F2, NF3 are similar, but those for PCl3 and CCl4 are smaller, relative to Ar(3P2). Improved rate constants for formation of individual N2(C,v’) levels from Ar(3P0) and (3P2) reacting with N2 at 300 K are given in the Appendix. [ABSTRACT FROM AUTHOR]

Space resolved concentrations of helium He* (S) and argon Ar* (P) metastable atoms in an atmospheric pressure radio frequency micro-plasma jet were measured using tunable diode laser absorption spectroscopy. Even small absorptions down to 10 could be measured using lock-in technique. The absolute density of metastable atoms densities at different rf-power, flow rate and gas mixture was deduced from measured absorption rates. Metastable concentrations range from 10 to 10 cm. Analysis of spectral profiles provided the pressure broadening coefficients of both metastable atoms by helium. The spatial distribution of metastable atoms in the plasma volume was obtained for various discharge conditions. Density profiles between the electrodes reveal the sheath structure and reflect the plasma excitation distributions in the discharge volume. It reveals the dominance of the α-mode discharge. [ABSTRACT FROM AUTHOR]

microplasma is generated in the microhole (400 μm diameter) of a molybdenum-alumina-molybdenum sandwich (MHCD type) at medium pressure (30-200 Torr) in pure argon. Imaging and emission spectroscopy have been used to study the sheath and electron density dynamics during the stationary normal regime and the self-pulsing regime. Firstly, the evolution of the microdischarge structure is studied by recording the emission intensity of the Ar (5 p[3/2]-4 s[3/2] $_{1})$ line at 427.217 nm, and Ar (4 p′P-4 s′D $_{5/2})$ line at 427.752 nm. The maximum of the Ar line is located in the vicinity of the sheath-plasma edge. In both regimes, the experimental observations are consistent with the position of the sheath edge calculated with an ionizing sheath model. Secondly, the electron density is recorded by monitoring the Stark broadening of the H $_\beta$-line. In the self-pulsing regime at 150 Torr, the electron density reaches its maximum value of 4 × 10 cm, a few tens of ns later than the discharge current maximum. The electron density then decays with a characteristic decay time of about 2 μs, while the discharge current vanishes twice faster. The electron density in the steady-state regime is two orders of magnitude lower, at about 6-8 × 10 cm. [ABSTRACT FROM AUTHOR]

Examines the transport of argon ions in an inductively coupled high-density plasma reactor. Details on the velocity distribution of the metastable ions; Need for a rapid and large area wafer processing in the semiconductor industry; Relevance of the ion velocity distribution function inside the presheath.

The quenching rate of the 750.4 nm actinometer line in argon by H 2 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, tie 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. [ABSTRACT FROM AUTHOR]