Radiative and collision rates of the different energy levels for the lower levels of the doublet states (upper panel) and upper levels of the doublet states (bottom panel). The rates were calculated for T_d = 100 K, T_k = 180 K, = 10^4.25 cm⁻³, and p = 1.15. Radiative up (black squares) means upward radiative excitation out of a state (absorption); radiative down (red filled circles) means the sum of spontaneous and stimulated emission rates; collisions (blue triangles) means total collision rate out of a state; radiative lower to upper (open circles) means radiative rate for absorption from the lower level of a doublet state to the associated upper level; collisions lower to upper (red diamonds) means the collision rate from the lower level of a doublet state to its associated upper level.