Line Positions and Intensities of ¹³C¹²CH₆ in the 12.2 µm Region

High-resolution, high signal-to-noise spectra of mono-substituted 13C-ethane (13C12CH6) in the 12.2 µm region have been recorded with a Bruker IFS 125HR Fourier transform spectrometer. Four of these spectra were recorded at three different temperatures between 130 and 208 K using a 99% 13C-enriched ethane sample contained in a 20.38-cm long coolable absorption cell1. A multispectrum nonlinear least squares fitting technique2 was used to fit the same intervals in these four spectra simultaneously to determine line positions and intensities. Similar to our previous analyses of 12C2H6 spectra in this same region3, constraints were applied to accurately fit each pair of doublet components arising from torsional Coriolis interaction of the excited ν12 = 1 state with the nearby torsional ν6 = 3 state. Line intensities are reported for 1660 ν12 absorption lines for which the assignments are known, and integrated intensities are estimated as the summation of the measured values. The measured line positions and intensities are compared with values in recent editions of spectroscopic databases.4




CC BY 4.0