THE MILLIMETER-WAVE AND SUBMILLIMETER-WAVE SPECTRUM OF TRANS-ETHYL ALCOHOL

The rotational-torsional spectrum of the trans rotational isomer of et hyl alcohol,was investigated in the 65-350 GHz frequency region, A tot al of 481 ground state transitions over a range of J and K-a values up to 33 and 10, respectively, were measured and assigned, Doublets or t riplets arising from the A and E torsional states of the v=O torsional level of the three-fold-symmetric methyl internal rotation have been resolved in 168 of these transitions, Internal rotation theory predict s a significant number of c-type E-state: transitions normally forbidd en, but allowed when the rotational asymmetry operators mix E-state ro tational-torsional levels, Over 40 of these transitions have been obse rved, The newly measured transitions, along with the results of many p revious measurements, have been analyzed using an IAM internal rotatio n Hamiltonian and a Watson A-reduced Hamiltonian to determine the rota tional, centrifugal distortion, and torsional constants, The IAM analy sis accounts for an of the analyzed transitions in the trans isomer, b ut for some applications-the: asymmetric rotor analysis is a satisfact ory description of the molecule, The J and K-a limits where the trans isomer can be analyzed without considering interactions with the gauch e states are also discussed, Predicted frequencies for transitions una ffected by the gauche states are presented through 600 GHz using the c onstants determined by this work, (C) 1995 American Institute of Physi cs and American Chemical Society.