Inspection of Table shows that all of the methods predict the correct configuration. However, at non-zero temperatures, one could argue that the single amine energy deltas for PBE (-9 kJ/mol), revPBE+GD2 (-7 kJ/mol), and RPBE+GD2 (-8 kJ/mol) are small enough that one would consider both configurations. In the case of the full pore, all methods predict the correct configuration, though the NNP prediction approaches degeneracy with the true prediction only being 8 kJ/mol more favorable than the alternate motif. These predictions are qualitatively summarized in Table . What's interesting about this amine and configuration is that it is known to take multiple stable conformations at room temperature, as mentioned before. It is thus surprising to have such uniform agreement across the board for the different methodologies employed, given that even at 100K, there doesn't seem to be a single motif, but freedom of movement. There has been evidence of amine swapping reported, as well . The c-aligned configuration, however, seems to suffer from strong enough steric repulsion along the c-axis that is unfavorable (without chemisorption of CO 2 ), meaning that it likely is not a physical motif.