To clearly outline the effect of this barrier on gas adsorption, we can chart paths on the osmotic landscape that are taken with adsorption and desorption, as shown in Figure , along with the associated amount adsorbed. Figure shows the path along which the system is in global thermodynamic equilibrium at each gas pressure, i.e. the path of lowest osmotic potential. On the other hand, Figure shows the kinetic path, along which transitions can occur only when the osmotic barrier between phases disappears. However, as thermal fluctuations can allow the crossing of barriers on the order of a few kBT , a transition was annotated on the osmotic landscape when the barrier was reduced to 15 kBT . The appropriate value of barrier heights that can be crossed by the system in typical timespans of experiments at a given temperature is difficult to obtain. For example, a fluctuation energy of 6 kBT per unit cell was proposed for a gate-opening MOF. Our analysis of the DUT-49 system demonstrates the same NGA transition at 120 K when this value of "crossable" barriers is varied between 0 and 25 kBT . For both the equilibrium and kinetic path, the system, at zero gas pressure, begins at equilibrium in the op phase, where there is also a metastable cp phase (with a unit cell volume of 50 nm 3 ). By increasing the gas pressure, the cp phase is stabilized with respect to the op phase, until the difference in osmotic potential between both phases vanishes at a gas pressure of 3.25 kPa. At this point, a transition occurs along the equilibrium path to the cp phase. This contraction produces a sudden increase in amount adsorbed, demonstrating a step of 236 molecules per unit cell. Conversely, no transitions occur along the kinetic path at this pressure, as a barrier between the op and cp phase of 591 kJ mol -1 remains. This barrier only vanishes at a gas pressure of 17.5 kPa, at which a op → cp transition occurs, associated with a NGA step of 86 molecules per unit cell. This predicted transition pressure is remarkably close to the observed value of 25 kPa. Although the predicted NGA step is underestimated compared to the observed value of 102 molecules per unit cell, the observation that the NGA phenomenon can be captured by traversing the osmotic surface obtained with an ab initio-derived force field is remarkable in itself. Further increasing the gas pressure to 25 kPa, the op phase again becomes the equilibrium phase, shown by the second transition in Figure . However, the barrier between both phases only disappears again at a higher gas pressure of 70 kPa, as shown in Figure .