Millimeter-Wave Spectra of the CO Dimer: Observation and Assignment of 20 New Transitions

Over 20 new millimeter-wave transitions of the 12C16O dimer are measured in the 77- to 186-GHz range using a coaxial pulsed jet spectrometer. Sixteen of these are unambiguously assigned using millimeter-wave combination differences, and three are tentatively assigned using infrared data. Some new or revised assignments of previously observed transitions are also proposed. The new results serve to locate a number of levels of the dimer for the first time with "microwave" ([less, approximate]0.1 MHz) accuracy. Such accuracy is important not just for its own sake, but also because it facilitates future assignments in the CO dimer spectra using precise combination differences.NRC publication: Ye