  Accurate line lists are important for the description of the spectroscopic
nature of small molecules. While a line list for CN (an important molecule for
chemistry and astrophysics) exists, no underlying energy spectroscopic model
has been published, which is required to consider the sensitivity of
transitions to a variation of the proton-to-electron mass ratio.
  Here we have developed a Duo energy spectroscopic model as well as a novel
hybrid style line list for CN and its isotopologues, combining energy levels
that are derived experimentally (Marvel), using the traditional/perturbative
approach (Mollist), and the variational approach (from a Duo spectroscopic
model using standard ExoMol methodology). The final Trihybrid ExoMol-style line
list for 12C14N consists of 28,004 energy levels (6,864 experimental, 1,574
perturbative, the rest variational) and 2,285,103 transitions up to 60,000 cm-1
between the three lowest electronic states (X2Sigma+, A2Pi and B2Sigma+). The
spectroscopic model created is used to evaluate CN as a molecular probe to
constrain the variation of the proton-to-electron mass ratio; no overly
promising sensitive transitions for extragalactic study were identified.
