MOLPOP-CEP non-LTE radiative-transfer model of the ground-state HFS lines of CH using a combination of collisional rate coefficients for collisions of CH with ortho-H₂, para-H₂, and atomic hydrogen all computed by Dagdigian (2018b). The blue, red, and dark orange curves represent the excitation temperatures of the 3.264 GHz, 3.335 GHz, and 3.349 GHz CH lines as a function of N(CH) for n = 5 × 10² (solid lines) and 5 × 10³ cm⁻³ (dashed lines), respectively, for models with T_kin = 75 K and Δυ= 6 km s⁻¹. The inset panel expands on the T_ex values for CH column densities between 10¹⁴–10¹⁵ cm⁻².