The 13C hyperfine constants of HCS and HSC studied by microwave spectroscopy

Abstract

The 13C hyperfine constants of the H 13CS and HS 13C radicals are determined by microwave spectroscopy. For H 13CS, the 1 01–0 00 rotational transition is measured at 38.5 GHz with a Fourier transform microwave spectrometer, and two 13C hyperfine constants are determined. They are well interpreted in terms of a relatively large HCS bonding angle (132.8°). For HS 13C, the N=7–6, 9–8, and 10–9 rotational transitions are measured in the 268–384 GHz region by using a source modulation spectrometer combined with a free-space discharge cell, and five 13C hyperfine constants including the nuclear spin–rotation constant, C aa , are determined. From the 13C hyperfine constants, the p character of the unpaired electron orbital on the carbon atom is estimated to be 66.5%, supporting a classical resonance picture; H ̇ S C↔ H S C ̇ .