Molecular complexes of organometallic molecules with noble gases: the rotational spectrum of dimethylsilane-argon

The rotational spectrum of the molecular complex dimethylsilane-argon was investigated by free-jet absorption millimeter-wave and molecular-beam Fourier transform spectroscopy. The absolute energy minimum corresponds to a conformation in which the argon atom lies in the plane of symmetry of dimethylsilane, perpendicular to the C-Si-C plane. The distance of Ar atom is tilted 14 degrees away from the Si atom. The zero-point dissociation energy was estimated from the centrifugal distortion constant D(J) to be 2.2 kJ mol(-1). Small splitting, due to tunneling of the Ar atom and internal rotation of the two methyl groups, was observed, measured, and used to determine the potential energy surface for these motions.