Structure and Dynamics of the Methane-Propane van der Waals Complex.

Microwave transitions in the region 7-26 GHz were measured for the methane-propane van der Waals complex. The nearly free internal rotation of methane within the complex gives rise to three states that do not relax even in a 5 K supersonic expansion. Eighteen lines have been assigned to the lowest state and are well fitted to a semirigid rotor model, with rotational constants A = 7553.

Microwave spectra and ab initio studies of Ar-propane and Ne-propane complexes: structure and dynamics.

Microwave spectra in the 7-26 MHz region have been measured for the van der Waals complexes, Ar-CH3CH2CH3, Ar-(13)CH3CH2CH3, 20Ne-CH3CH2CH3, and 22Ne-CH3CH2CH3. Both a- and c-type transitions are observed for the Ar-propane complex. The c-type transitions are much stronger indicating that the small dipole moment of the propane (0.