ab initio calculation of S-33 quadrupole coupling constants. Reanalysis of the S-33 hyperfine structure in the rotational spectrum of thiirane

We present quantum chemical calculations on the MP4(SDQ) level with basis sets of high local quality to determine the nuclear quadrupole coupling tensor of S-33 series of molecules, which of were investigated up to now by microwave spectroscopy. The analysis of the nuclear quadrupole coupling in the rotational spectra provided experimental information on the tensors. As an example for such an analysis, improved values for thiirane, (C2H4S)-S-33, are given: chi(aa)=-32.9425(78) MHz, chi(bb)=-16.402(14) MHz, chi(cc)=49.345(14) MHz.