N2
N2 comparisons are limited to B3LYP-D3 and B97-D3. B3LYP
simulations do not have the dispersion calculations necessary to adsorb
N-N to the catalyst, as DFT cannot accurately describe the types of
dispersion forces that would exist between N2 and the
metal surfaces.31 Therefore, no N2simulations converged with B3LYP. The binding energies calculated for
the other methods are shown in Figure 5 with respect to the angle of
adsorption on the catalyst surface (N-N bond with Ir surface). B97-D3
suggests that the end-on configuration is favorable for both (111) and
(100) surfaces. This position hovers at the top site, in agreement with
Krekelberg.38 B3LYP-D3 suggests that there are
multiple orientations of N2 within 0.05eV that
successfully adsorb, with the lowest energy configurations being mostly
parallel to the surface (side-on) for both (111) and (100).