Spectroscopy of CD3OD

Our resulting model describes the ground and first excited torsional states of CD_3_OD well up to quantum numbers J<=51 and Ka<=23. We derived a line list for radio-astronomical observations from this model that is accurate up to at least 1.1THz and should be sufficient for all types of radio-astronomical searches for this methanol isotopolog. This line list was used to search for CD_3_OD in data from the Protostellar Interferometric Line Survey of IRAS 16293-2422 obtained with the Atacama Large Millimeter/ submillimeter Array.

While we found several emission features that can be attributed largely to CD_3_OD, their number is as yet insufficient to establish a clear detection. Nevertheless, the estimate of 2x10^15cm^-2^ derived for the CD3OD column density may be viewed as an upper limit that can be compared to column densities of CD_3_OH, CH_3_OD, and CH_3_OH. The comparison indicates that the CD_3_OD column density toward IRAS 16293-2422 is in line with the enhanced D/H ratios observed for multiply deuterated complex organic molecules.