Spectral Line Parameters in the ν9 Band ofEthane

Spectral line parameters, including line center positions, absolute line intensities, self- and N2-broadened halfwidth coefficients, and the temperature dependences of these halfwidth coefficients, have been measured for more than 1330 transitions in the ν9 band of ethane (C2H6) by applying a multispectrum nonlinear least squares analysis technique.1 We analyzed a total of 43 high-resolution (0.00156-0.005 cm−1) infrared absorption spectra recorded with two different Bruker Fourier transform spectrometers (at PNNL and at JPL) at various sample path lengths, pressures and temperatures. The ν9 fundamental of C2H6 is the strongest band in the terrestrial spectral window, and it is often used for ethane identification and abundance determination in remote sensing of planetary atmospheres. Torsional splittings are fairly large (dependent upon J;K) and measurable in several rQ and pQ sub-band structures. However, in the case of the rQ0 sub-band the two split components are completely obscured because of the overlap of Doppler-broadened J transitions. The results from the present study2 will be compared with other published data.