MICROWAVE STUDIES ON THE ARGON VAN DER WAALS CLUSTERS OF AROMATIC COMPOUNDS

Abstract

We will report on our pulsed molecular beam microwave Fourier transform experiments on the argon complexes of a number of aromatic compounds. We investigated the relation between substituents at the benzene ring and the structure of the argon complexes in the case of $fluorobenzene^{1}$, $1,2-difluorobenzene^{2}$, 1,2,4-trifluorobenzene, 1,2,3,5-tetrafluorobenzene, and benzonitrile. We were also interested in the location of the argon atom in the complexes of the heterocyclic compounds thiophene, oxazole, isoxazole, and thiazole. Rotational and centrifugal distortion constants will be presented and discussed in terms of structural parameters and of force constants of the van der Waals bonds as determined from centrifugal distortion constants. In the case of benzonitrile, oxazole, and thiazole we will also give the nitrogen quadrupole coupling constants which can be considered as an additional source of structural information.