The B11244 story: rovibrational calculations for C3H(+) and C3H(-) revisited.

New theoretical values for the rovibrational parameters of C3H(+) and C3H(-) in the ground vibrational states are reported for the quartic internal coordinate force fields constructed by Huang et al. [Astrophys. J., Lett. 768, L25 (2013)] and Fortenberry et al. [Astrophys. J. 772, 39 (2014)]. Effective spectroscopic parameters are derived from the rovibrational energies, calculated up to J = 20 for C3H(+) and J = 12 for C3H(-) by means of a computational strategy for numerically exact rovibrational computations. Our results help to resolve a disharmony between the experimental observations and previous theoretical predictions in the case of C3H(+): we show that the previously used perturbational approach is not sufficient to reliably predict relevant spectroscopic properties of C3H(+) and that the force field of Huang et al. in combination with the numerically exact rovibrational treatment in fact supports the experimental identification of C3H(+), in contrast to the original conclusion of Huang et al. and Fortenberry et al. that the astronomical assignment of the B11244 carrier to C3H(+) is incorrect.