Molecular complexes of organo-metallic molecules with rare gases: the rotational spectrum of difluorodimethylsilane-argon

The rotational spectrum of the molecular complex difluorodimethylsilane-argon has been investigated by pulsed jet absorption millimeter wave and pulsed supersonic jet Fourier transform microwave spectroscopy. The absolute energy minimum corresponds to a conformation with the argon atom lying in the F-Si-F plane of symmetry of difluorodimethylsilane. This is confirmed by the analysis of the observed splitting due to the internal rotation of two equivalent methyl groups. The V-3 barrier to the internal rotation of the two methyl groups has been determined to be 4.857(5) kJ/mol. The distance of Ar from the center of mass of difluorodimethylsilane is 4.07 angstrom, with Ar-Si line forming an angle of 60.6 degrees with the C-Si-C bisector. The zero point dissociation energy is estimated, from the centrifugal distortion constant D-J, to be 2.75 kJ/mol. (c) 2004 Elsevier B.V. All rights reserved.