The minimum error is found for the adsorption enthalpy at 900 K, which gives an RMSE of 1.76 kJ mol -1 instead of 2.87 kJ mol -1 for the 298 K case. This new type of descriptor is very interesting since it performs better around the high selectivity region, where the standard Boltzmann average at 298 K loses its accuracy (see Figure ). As shown on Figure , the exchange free energy at 900 K and the excess of free energy compared to the 298 K case are the second and third most influential descriptors of our ML model. They are complementary to the exchange free energy at 298 K to predict selectivity values at higher pressures.