Abstract: | Pure rotational transitions in the ground vibrational state have been measured for H212C18O, H212C17O, H213C18O, and H213C17O in the frequency region 8–75 GHz. These have included both Q- and R-branch transitions, and have permitted accurate evaluation of rotational constants and several quartic centrifugal distortion constants for each species. These in turn have permitted the prediction of several transitions of possible use in radioastronomy. |