THE ROTATIONAL SPECTRA, HYPERFINE INTERACTIONS, AND O-17 MAGNETIC SHIELDINGS OF (OOO)-O-17-O-16-O-16, (OOO)-O-16-O-17-O-16, AND (OSO)-O-17-O-16

Measurement of the rotational spectra of (OOO)-O-17-O-16-O-16 and (OOO )-O-16-O-17-O-16 have been extended to allow the determination of a co mplete set of sextic centrifugal distortion constants for both molecul es. A near degeneracy of the 3(12) and 4(04), levels of (OOO)-O-17-O-1 6-O-16 causes strong perturbations of the hyperfine patterns, gives ri se to perturbation-allowed Delta J = 2. transitions, and provides an a ccurate determination of chi(ab). This has allowed the calculation of the angle between the principal axis of the quadrupole tenser and the O-O bond. The O-17 spin-rotation interactions of (OSO)-O-17-O-16 have been measured for comparison with the corresponding values in O-3, and improved values of the quadrupole coupling have been obtained. Parama gnetic shielding and chemical shifts for O-17 have been calculated fro m the spin-rotation constants for both compounds.