Laboratory detections of SiC2N and SiC3N by Fourier transform microwave spectroscopy

Two silicon-bearing carbon chain radicals, SiC2N and SiC3N, were detected in the laboratory by Fourier transform microwave spectroscopy. Molecular constants including the hyperfine coupling constants have been determined for the two radicals in the ground electronic states. The SiC2N and SiC3N radicals have linear structures in the (2)Π ground electronic states with inverted and regular fine structures, respectively, as are the cases for their isoelectronic radicals, SiC3H and SiC4H, indicating that the SiC(n)N radicals have similar electronic structures to the SiC(n +1)H radicals. The electronic structures of SiC2N and SiC3N in the ground states are discussed on the basis of the experimentally determined molecular constants.