Distribution of the total gas pressure onto its various components for a model of T_eff =2500 K. As indicated with the legend, the curves show the partial pressures of the molecules H₂ , CO, H₂O, CH₄ , NH₃ , TiO, and OH, the neutral H and He atoms, the sum of all positively charges species (“pel+”), all negatively charged species (“pel-”), sum of the partial pressures of all neutral atoms together (“pnat”), all neutral molecules (“pnmo”), and finally the sum of all the opacity bearing molecules in the classical MARCS models (“p24m”) as well as in the new models presented here (“p54m”). We note that the curves for H₂ and all neutral molecules (pnmo) as expected plot on top of one another, as do the curves p24m and p54m (therefore p24m/p54m show as a single full drawn green curve, and the only red curve is for the partial pressure of TiO). The upper black curve is for H and the lower for NH₃ .