Hyperfine analysis of the microwave spectrum of the vinylthio radical, CH2CHS

Measurement of pure rotational transitions for the vinylthio radical, CH2CHS, previously observed by Fourier-transform microwave spectroscopy (Nakajima et al., 2007), are extended to a number of fine and hyperfine component lines split by the unpaired electron spin and the three non-equivalent protons. All the measured transition frequencies have been analyzed by a Hamiltonian for doublet asymmetric top molecules with hyperfine interaction terms for three nuclear spins, yielding precise molecular constants of CH2CHS in the ground state. Discussions on the electronic structure of CH2CHS are given based on the determined molecular constants. (C) 2018 Elsevier Inc. All rights reserved.