THE HIGH-RESOLUTION FOURIER-TRANSFORM SPECTRUM OF DIDEUTERATED METHANE CH2D2 IN THE REGION BETWEEN 1900 AND 2400 CM(-1)

The infrared spectrum of doubly deuterated methane CH2D2 has been reco rded in the region from 1900 to 2400 cm(-1) at almost Doppler-limited resolution by using two high-resolution Fourier transform spectrometer s. The vibrational bands observed include 2 nu(4), nu(4) + nu(7), 2 nu (7), nu(2), nu(8), nu(4) + nu(9), and nu(7) + nu(9), which were analyz ed by taking into account Coriolis and Fermi interactions among them a nd also those with nu(4) + nu(5), nu(3) + nu(7), and nu(5) + nu(7). Mo st of the centrifugal distortion constants were constrained to appropr iate values, while the vibrational term value and three rotational con stants in each of the seven excited states were adjusted along with Co riolis and Fermi interaction parameters by the least-squares analysis of the observed spectrum. The vibration-rotation interaction constants alpha(s) thus determined for the nu(2) and nu(8) states were combined with those of other fundamental states already published to calculate the equilibrium C-H distance. (C) 1996 Academic Press, Inc.