Submillimeter-wave spectroscopy of HCNH+ and CH3CNH+

The pure rotational transitions of HCNH+ and CH3CNH+ have been measured up to 750 GHz for HCNH+ and in the range of 325–500 GHz for CH3CNH+. The presented molecular constants of HCNH+ are a definite improvement over previously determined values. Submillimeter-wave lines for CH3CNH+ have been observed for the first time and the accuracy of the molecular constants has been improved, compared with that attained by infrared measurements.