High-resolution FTIR spectroscopy of the nu(11) and nu(2)+nu(7) bands of ethylene-d(4)

The Fourier transform infrared spectrum of the nu(11) band of ethylene-d(4) (C2D4) has been recorded with an unapodized resolution of 0.006 cm(-1) in the frequency range 2150 to 2250 cm(-1). The nu(11) band, with a band centr e of about 2201 cm(-1), was found to be perturbed by the nearby nu(2) + nu( 7) band centred at about 2235 cm(-1) by a b-type Coriolis interaction. By f itting a total of 772 infrared transitions of nu(11) using a Watson's A-red uced Hamiltonian in the I-r representation with the inclusion of b-type Cor iolis interaction term, two sets of constants, up to quartic distortion con stants for the upsilon(11) = 1 state, and principal rotational constants fo r the upsilon(2) + upsilon(7) = 1 dark state, were derived. The inertia def ect of the nu(11) state was found to be 0.0693 +/- 0.0004 u Angstrom(2).