The Rotational Spectrum of the Benzene‐Carbonyl Sulfide Complex. A Contribution to the Theory of Internal Rotation with Heavy Tops

The rotational spectra of the four isotopomers normal, d1, d6, 18O of the benzene‐carbonyl sulfide complex, C6H6 ‐ OCS, have been analyzed. The interpretation of the rotational spectra as quasi symmetric top spectra has been deduced from the internal rotation theory. Most probably the carbonyl sulfide is perpendicular to the plane of benzene with sulphur towards benzene. The distance between the centers of mass of the partners is 4.42 Å.