Pure Rotational Spectrum of CN⁺

Abstract

Abstract The pure rotational spectrum of the elusive CN + cation has been observed for the first time using a cryogenic ion trap apparatus and applying an action spectroscopy scheme. For the 12 C 14 N + species, the three lowest rotational transitions have been observed, each of which exhibits hyperfine structure from the presence of the 14 N nucleus. The rare C 15 N + isotopologue has been studied up to the J = 4 − 3 transition. The observations conclusively confirm that CN + occupies a 1 Σ + electronic ground state. Given the ubiquity of the CN radical in space, CN + is an appealing candidate for future radio astronomical searches.