Knowledge Bank

Water-carbon dioxide complexes are formed in a supersonic expansion and their rotational spectra are measured between 0.5 MHz and 18 GHz using a molecular beam electric resonance spectrometer. Rotational constants are obtained from the data along with other structural constants are obtained from the data along with other structural information. The geometry is T-shaped and planar ($C2v$ symmetry ) with the oxygen in the water bound to the carbon and the hydrogens directed away from the $CO2$. Other parameters are given in the following table. The C - O distance is determined by optimizing a planar structure to fit $B+C$. [FIGURE] A spectrum calculated using a semirigid rotor model does not reproduce the observed transitions within experimental error but the difference between the observed and calculated values is within a few hundred kHz in each case. The presence of hindered internal rotation is interred.