The S Nuclear Quadrupole Coupling in the Rotational Spectrum of awri-2,3-Dimethylthiirane

The rotational spectrum of an//-2,3-dimethylthiirane, CH 3 -C 2 H 2 S-CH 3 , was recently investigated in our laboratory [1]. In this study the rotational spectra of the normal, 3 S, and l 3 C isotopomers were measured, assigned and analysed for internal rotation and the molecular structure. The present communication aims at the nuclear quadrupole coupling of the 3 S isotopomer, measured in natural abundance. The nuclear quadrupole coupling tensor contains data on the S-C bonds in the thiirane ring and together with supplementary work on methylthiirane [2], CH 3C 2 H 3 S, 2,2-dimethylthiirane, (CH 3 ) 2 -C 2 H 2 S, and thiirane, C 2 H 4 S, we hope to get information on the effect of the methyl substitution of the thiirane ring. The results will also serve as experimental background for quantum chemical calculations [3]. This work is part in a program devoted to 3 S quadrupole coupling. Up to now the 3 S hyperfine structure of eight molecules [ 4 1 1 ] was investigated during this course by Fourier transform microwave spectroscopy [ 12] in our laboratory.