The structure of the Ar ⋅ CH3Cl van der Waals molecule

Eleven new radio frequency and microwave transitions have been observed in Ar ⋅ CH3Cl. Combining this data with the previously unassigned microwave spectrum [J. Chem. Phys. 71, 4189 (1979)] produced a satisfactory fit of the data. The structure obtained places Ar 3.68 (1) A from the CH3 Cl center of mass in an orientation perpendicular to the symmetry axis. Ar ⋅ CH3 Cl represents the first contradiction of simple donor–acceptor models for predicting the structure of van der Waals molecules.