THE ROTATIONAL SPECTRUM OF THE ISOTOPICALLY SUBSTITUTED VANDERWAALS COMPLEX AR-OCS, OBTAINED USING A PULSED-BEAM MICROWAVE FOURIER-TRANSFORM SPECTROMETER

A sensitive new pulsed beam cavity microwave Fourier transform spectrometer has been constructed. It has been used to measure for the first time the pure rotational spectra of the van der Waals complexes ArO13CS, Ar18OCS and Ar17OCS, and to measure further transitions of ArOC34S. Rotational and centrifugal distortion constants have been determined for all species, as well as 17O quadrupole coupling constants in Ar17OCS. A harmonic force field has been obtained for the van der Walls motions, and has been used to reproduce the variations of distortion constants with isotopomer. Both substitution and ground state average structures have been evaluated. It is confirmed that the complex is a loose binding of Ar and OCS, with little change in the structural parameters of OCS from those of the free molecule. © 1992.