Measurement of C2 and CH temperatures in argon‐acetylene low‐pressure microwave‐induced plasma

• Published in: Contributions to plasma physics (1988) Vol. 59; no. 7
• Main Authors: Jovović, J., Majstorović, G.Lj
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY‐VCH Verlag GmbH & Co. KGaA 01.08.2019; Wiley Subscription Services, Inc
• Subjects: Acetylene; Argon; carbon molecule; Emission spectra; Gas mixtures; Gas temperature; Helium; hydrocarbon molecule; microwave‐induced plasma; optical emission spectroscopy; plasma diagnostics; rotational temperature measurement; spectral line shapes and intensities
• ISSN: 0863-1042; 1521-3986
• DOI: 10.1002/ctpp.201800147

The emission spectra of C2(d3Πg–a3Πu), CH(A2Δ–X2Π), and CH(B2Σ–X2Π) bands are analysed to measure rotational Trot, vibrational Tvib, and gas temperature Tg from Ar/C2H2 (5–20% C2H2) microwave‐induced plasma (MIP). In case when helium and hydrogen are used in the gas mixture instead of argon, no significant change in Trot is noticed. Both studied temperatures are insensitive in terms of the C2H2 percentage. From CH(0–0, A2Δ–X2Π) band R2 branch lines, two Trot (Trot ∼ 520–580 K for J′ = 3–9 and Trot ∼ 1,700–1,800 K for J′ = 10–17) are determined. The lower Trot equals the Tg (500–700 K) measured from C2 bands in this study. The H2 Fulcher‐α diagonal bands are recorded as well in the H2/C2H2 mixtures and Trot∼750–900 K of the H2 ground state measured. Tvib ∼ 6,000 K in Ar/C2H2 MIP is calculated from the integral intensity ratio of C2(2,1) and C2(3,2) bands. A spectroscopic diagnostics of acetylene‐containing microwave‐induced plasma source is presented. A set of well‐resolved C2 and CH emission bands is analysed to measure Trot, Tvib, and Tg in Ar/C2H2, He/C2H2, and H2/C2H2 gas mixtures. The knowledge of Tg in this type of plasma source is of particular interest in the field of deposition of carbon‐containing and hydrocarbon‐containing layers.