A NEW ANALYSIS OF THE ROTATIONAL SPECTRUM OF CH3OD

Using an extended version of the internal axis method previously introduced to analyze the rotational spectrum of methanol to microwave accuracy, we have reanalyzed new and existing data for CH3OD in the three lowest torsional levels (vt = 0, 1, 2). As in the case of CH3OH, we have succeeded in fitting the spectrum to the accuracy of our experiment (50-100 kHz) by dividing the data into two sets according to the symmetry species (A or E) of the torsional sublevels, and by adding a number of terms to the Hamiltonian to describe to high order the interaction between torsional motion and end-over-end rigid body rotation. Specifically, 226 transitions in the A symmetry levels and 246 transitions in the E symmetry levels involving rotational quantum number J ≤ 9 were fit to root-mean-square deviations of 81 and 92 kHz, respectively. © 1993 Academic Press, Inc.