Carbon–sulfur chains: A high‐resolution infrared and quantum‐chemical study of C3S and SC7S

Abstract

AbstractIn the course of a 5 μm high‐resolution infrared study of laser ablation products from carbon–sulfur targets, the ν1 vibrational mode region of linear C3S has been studied continuously from 2046 to 2065 cm−1. Besides the prominent vibrational fundamental, the region was found to feature the , and even hot bands, the latter two of which were observed for the first time. Owing to the high signal‐to‐noise ratio obtained, the ν1 mode of S could also be observed in natural abundance for the first time at high spectral resolution in the infrared. At 2061 cm−1, hidden inside the branch of the C3S ν1 fundamental mode, a weak new band is observed which exhibits very tight line spacing and stems from a heavy both carbon and sulfur containing carrier. On the basis of high‐level quantum‐chemical calculations of selected carbon–sulfur chains and other carbon‐rich cumulenes, this feature is attributed to the ν5 vibrational fundamental of linear SC7S, which stands for the first gas‐phase spectroscopic detection of this long cumulenic chain.