The First Laboratory Detection of Vibration-rotation Transitions of 12CH+ and 13CH+ and Improved Measurement of Their Rotational Transition Frequencies

5 pags., 2 figs., 5 tabs.C-H stretches of the fundamental ions CH and CH, which have long been searched for, have been observed for the first time in the laboratory. The state-dependent attachment of He atoms to these ions at cryogenic temperatures has been exploited to obtain high-resolution rovibrational data. In addition, the lowest rotational transitions of CH, CH and CD have been revisited and their rest frequency values have improved substantially.This work (including the research visit of J.L.D. to Köln) has been supported by the Deutsche Forschungsgemeinschaft (DFG) via SFB 956 project B2 and the Gerätezentrum “Cologne Center for Terahertz Spectroscopy.” J.L.D. acknowledges partial support from the Spanish MINECO through grant FIS2016-77726-C3-1-P and from the European Research Council through grant agreement ERC-2013-SyG-610256 NANOCOSMOS.Peer Reviewe