Microwave torsional-rotational spectra of gauche CH3CD2OH and CH3CD2OD

The microwave torsional-rotational spectra of gauche CH3CD3OH and CH3CD2OD have been identified, assigned, and analyzed up to 70 GHz. From the observe d a- and c-dipole transitions, it has been possible to determine the effect ive rotational coefficients and the gauche tunneling energy of the hydroxyl internal rotation. The product of inertia terms I-xy and I-xz were include d in the analyses using the framework fixed axis method (FFAM) approach to the hydroxyl internal rotation. Further, the analyses were sensitive to sel ected effective centrifugal distortion coefficients. For CH3CD2OH, a-dipole Lines were assigned for the first excited gauche state. As for CH3CH2OH, t hese lines were highly nonrigid rotor in behavior more than likely due to t he resonance with the first excited state of the methyl torsion. (C) 2000 A cademic Press.