Abstract

The highest peak in Cassini's INMS data for stratospheric flybys of Titan's atmosphere is m/z = 28. While this has mostly been attributed to HCNH+, minor contributions from N-2(+) and C2H2+ are also likely. However, this work shows that :CNH2+ may also be present in a kinetically-favorable potential well based on high-level quantum chemical computations. The ionization energy of N-2 is much higher than the isomerization barrier between HCNH+ and :CNH2+. As such, we present computations that provide vibrational and rotational spectroscopic data for the possible remote sensing of this molecule in Titan's atmosphere. Such data are also computed for the isoelectronic :CCH2 molecule, and comparison to previous laboratory experiments and quantum chemical computations, where available for the hydrocarbon, is excellent. Consequently, the data provided in this work should allow for initial searches for :CNH2+ as well as refinements of data for :CCH2 both in the laboratory and even in Titan's atmosphere