THE MICROWAVE SPECTRUM AND STRUCTURE OF THE $(CH_{3})_{2}O - SO_{2}$ COMPLEX

Author Institution: Department of Chemistry, University of MichiganThe microwave spectra of $[CH_{3}]_{2}O- SO_{2}$ have been observed with a pulsed beam. Fourier transform microwave spectrometer. In addition to the normal isotopic form, we have observed the spectra of $(CH_{3})_{2}O {^{34}}SO_{2}, {^{13}}CH_{3}OCH_{3} - SO_{2}. (CH_{3})_{2}O - S_{16}O_{18}O$, and $(CH_{3})_{2}O - S_{18}O_{2}$. The transitions are characterized by both a- and c-type selection rules. The rotational constants (in MHz) for $(CH_{3})_{2}O. SO_{2}$ are $A = 4536.869(23), B = 1865.145(1)$ and $C = 1457.854(1)$. Stark effect measurements give electric dipole components of $\mu_{a} = 1.860(1)$ and $\mu_{c} = 0.591(1)$ Debye. The dipole components and moment of inertia data show that the complex belongs to the Cs point group. The two monomers are separated by $3.05 {\AA} (R_{cm})$. The structure of this complex, after fitting the derived moments of inertia, has the planes of the two monomer units in an approximately parallel stacked configuration with the oxygen atom of the ether closest to the sulfur atom of $SO_{2}$. There is no evidence for methyl group internal rotation splittings