Laboratory Spectroscopy and Herschel and APEX Observations of Light Hydride Species

I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, Germany ;
e-mail: hspm@ph1.uni-koeln.de

Abstract

Observations of CH⁺, J = 1 − 0 and 2 − 1 near 0.835 and 1.67 THz with Herschel/HIFI and of ¹³CH⁺, J = 1 − 0 near 0.830 THz with APEX revealed their rest frequencies to be higher than the accepted values by 21 and 30 km s^-1, respectively. Very recent laboratory measurements of the J = 1 − 0 transition frequencies of CH⁺, ¹³CH⁺ and CD⁺ and fits to these as well as electronic spectral data resolved the descrepancies. The laboratory spectroscopic situation will be reviewed for selected cationic light hydride species.