THE MICROWAVE SPECTRUM AND STRUCTURE OF FLUOROBENZENE $\bullet$ SULPHUR DIOXIDE

Abstract

The Fourier transform microwave spectra of fluorobenzene $\bullet$ sulphur dioxide and four isotopomers $(^{34}S, two ^{18}O, and d-5)$ have been observed. The dimer has a stacked structure with the $SO_{2}$ over the fluorobenzene ring straddling a symmetry plane. The dipole moments of $SO_{2}$ and $C_{6}H_{5}F$ are oriented approximately antiparallel in the symmetry plane. The center of mass distance $(R_{em})$ is $3.62(5) \AA$. The $SO_{2}$ plane is tilted relative to the fluorobenzene plane by $24^{\circ}$ with the sulphur closer to the aromatic plane.