Comparison of various ion density profiles based on our solar minimum model calculations, along with the total ion (or electron) density profile (denoted as “e”). The solid lines show our nominal model results with the ${\text{CO}}_2^{+}+\text{O}$ reaction rate constants adapted from the conventional Fehsenfeld et al. (1970)’s values, whereas the dashed lines show the results based on the new laboratory measurements of the same reaction rate constants reported in Tenewitz et al. (2018).