Toward an f‑Band Theory for the Actinides: DFT Studies of Small Molecule Adsorption on Np- and Am-Substituted PuO2 Surfaces.

Np- and Am-substituted surfaces were constructed from the stoichiometric PuO2 {110} surface. Density functional theory simulations reveal the effects of neighboring Np and Am atoms, and their influence on the Pu 5f-band properties is analyzed. Linear relationships are observed between the 5f-band properties and the number of neighboring Np or Am atoms. Small molecules (water and nitric oxide) were used as probes, and their adsorption behaviors were compared across the substituted surfaces. Notable correlations are found between the 5f-band properties and adsorption energies. These findings suggest the potential to develop an f-band theory for actinides analogous to the well-established d-band theory for transition metals.