Line-Mixing Effects in He- and N2-Broadened Σ ← Π Infrared Q Branches of C2H2

✍ Scribed by Jean-Pierre Bouanich; Ghislain Blanquet; Jacques Walrand

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 160 KB
• Volume: 203
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.2000.8160

✦ Synopsis

Two Q branches of C 2 H 2 near 716.3 and 719.9 cm Ϫ1 belonging to the ( 4 ϩ 5 ) 0 Ϫ 4 1f and 2 5 0 -5 1f bands, of ⌺ 4 ⌸ symmetry, have been studied for He and N 2 perturbers at pressures ranging from 0.05 to 1 atm, using a tunable diode-laser spectrometer. To interpret the line-mixing effects observed in these spectra, we have applied a model based on the energy-corrected sudden approximation whose parameters have been only derived from line-broadening data. This model provides satisfactory agreement with experimental bandshapes for both bands and perturbers, especially at pressures higher than 0.1 atm. The Q-branch profiles for C 2 H 2 -He are higher and narrower than those obtained for C 2 H 2 -N 2 at the same pressure as the result of smaller broadening coefficients and larger line-mixing effects in the former system.