2012ApJ...760...57T

A comparison between the widths of ion and neutral molecule spectral lines has been recently used to estimate the strength of the magnetic field in turbulent star-forming regions. However, the ion (HCO⁺) and neutral (HCN) species used in such studies may not be necessarily co-evolving at every scale and density, and thus, may not trace the same regions. Here, we use coupled chemical/dynamical models of evolving prestellar molecular cloud cores including non-equilibrium chemistry, with and without magnetic fields, to study the spatial distribution of HCO⁺ and HCN, which have been used in observations of spectral line width differences to date. In addition, we seek new ion-neutral pairs that are good candidates for such observations, because they have similar evolution and are approximately co-spatial in our models. We identify three such good candidate pairs: HCO⁺/NO, HCO⁺/CO, and NO⁺/NO.