Infrared rotation-vibration spectra of ethane: The parallel band, 2ν3, of CH3CD3

The parallel band, 2ν₃, of CH₃CD₃ is measured in the region 2715 to 2780 cm^?1 under a spectral resolution of ～0.025 cm^?1, increased to ～0.015 cm^?1 by deconvolution. About 460 lines are identified in the 2ν₃ band, and about 240 lines in a hot band arising from the first excited torsional state. Least-squares analyses with Δ₂F″ combination differences yield lower-state parameters. An individual subband analysis is undertaken because of perturbations in the vibrational bands studied. Finally, band constants are derived.