Reflection spectroscopy study of the 16O12C16O ν3-band lines

•Measurements of broad band reflection CO2 gas spectra.•Absolute determination of the CO2 gas refractive index.•Validation of spectroscopic data.•Toward refractive index measurements of tightly confined gases are discussed.

Reflection spectra of pure CO2 gas have been recorded in the 4.3μm region by using a high resolution Fourier transform spectrometer, providing measured values of the refractive index. Comparisons with the results of calculations using available spectroscopic data, and free of any adjusted line parameter, show a very good agreement. This confirms that this experimental technique provides an alternative approach for the test or determination of spectroscopic parameters. Its advantages for studies of extremely strongly absorbing species and investigations of spatially (tightly) confined molecular gases are discussed.