The rotational spectrum of SO2 and the determination of the hyperfine constants and nuclear magnetic shielding tensors of (SO2)-S-33 and (SOO)-O-17

Precise frequencies for the 1(11)-2(02) transition of (SO2)-S-33 and (SOO)- O-17 in natural isotopic abundance have been obtained near 12 GHz by microw ave Fourier transform spectroscopy in order to yield improved hyperfine con stants. Nuclear spin-rotation coupling constants have been determined exper imentally for (SO2)-S-32 for the first time. The spin-rotation constants ha ve been used to derive nuclear magnetic shielding, parameters. These parame ters are compared with values for the isoelectronic O-3 molecule. The trans ition mentioned above was also measured for (SO2)-S-32, (SO2)-S-34 (SOO)-O- 18, and vibrationally excited (v(2) = 1) (SO2)-S-32. For (SO2)-S-33,, some transitions with large hyperfine splitting were also recorded in the millim eter-wave region. Continuing our investigations of the rotational spectra o f SO2 in the submillimeter region, several transitions of (SOO)-O-17 have b een recorded with the Cologne terahertz spectrometer between 540 and 840 GH z with J and K-a, up to 63 and 16, respectively. Transitions with high K-a, up to 28, have been recorded with the JPL laser sideband spectrometer betw een 1.8 and 3.2 THz. (C) 2000 Academic Press.