Quantitative Raman Spectroscopic Determination of the Composition, Pressure, and Density of CO₂-CH₄ Gas Mixtures

Figure 2

Raman spectrum of the CO₂-CH₄ mixture showing the Raman lines for CO₂ and CH₄. The top left insert shows the detailed spectrum of CO₂ containing Fermi diad bands, two hot bands, ¹³CO₂, and the spectrum for benzonitrile. The two marked peaks for benzonitrile (1192.6 and 1598.9 cm⁻¹) were used to calibrate the CO₂ Fermi diad splitting. The right insert shows the C-H symmetric υ₁ band of CH₄ and Ne emission lines at 2836.976 cm⁻¹, 2933.916 cm⁻¹, and 3008.127 cm⁻¹. The Ne emission lines at 2836.976 cm⁻¹ and 2933.916 cm⁻¹ bracket the υ₁ band of CH₄ and were used to calibrate the CH₄υ₁ peak position.