Non-LTE mechanism for a model at roughly solar parameters (T_eff = 5750 K, log 𝑔 = 4.5 cm s⁻², [Fe/H]= 0) in the left panels and for a hotter star (T_eff = 7000 K, log 𝑔 = 4.0 cm s⁻², [Fe/H]= 0) showing larger departures from LTE in the right panels. In each case, the upper panel shows the run of the departure coefficient b_ with the logarithm of the optical depth at 500 nm, log τ₅₀₀. The second panel shows the ratio R^†/R. The third panel shows the photodetachment rate per H⁻ ion R and effective collisional rate per H⁻ ion r. The lowest panel shows the temperature T. In each case, models with standard convection for MARCS models (mixing length parameter α = 1.5, thinner blue lines) and without convection (α = 0, thicker orange lines) are shown.