Infrared Spectra of the Water-CO Complex in the 4.3-3.6 μm Region and Determination of the Ground State Tunneling Splitting for HDO-CO.

Spectra of water─CO dimers are studied using a tunable mid-infrared source to probe a pulsed slit jet supersonic expansion. HO-CO and DO-CO are observed in the CO ν fundamental region (≈2350 cm), DO-CO is also observed in the DO ν fundamental region (≈2790 cm), and HDO-CO is observed in the HDO O-D stretch fundamental region (≈2720 cm), all for the first time in these regions. Analysis of the spectra yields excited state rotational parameters and vibrational shifts.