(360y) The Nuclear and Surface Electrostatic Potential As Descriptors of Chemical Interactions

The electrostatic potential, V(r), evaluated at the atomic nucleus or on the isodensity surface of a chemical compound can be used to make predictions about its local interaction tendencies. Chemical bonding is a central concept in chemistry and the ability to predict and explain interactions between chemical compounds allows the chemist to synthesize complex molecules and materials, estimate their chemical properties, and forecast their degradation. In this presentation, we discuss the advantages of using V(r) for predictions of chemical interactions between adsorbates and material surfaces – interactions of importance in, e.g., catalysis, corrosion, and nanotechnology. V(r) is a local property and its variations over a compound can be used to identify sites that are prone to interactions with either electron-acceptors (negative regions in V(r)) or with electron-donors (positive regions). The figure demonstrates the approach using a gold nanoparticle as example. Here, V(r) is mapped on a 0.001 au isodensity surfaces – known as the surface electrostatic potential, V_S(r). Red regions on the map are positive and found on atop sites. These interact with electron-donors such as the lone-pairs of H₂O, whereas negative (blue) areas found at hollow sites are susceptible to interactions with electron-acceptors such as the H-end of H₂O. Variations in the magnitude of V_S(r) correctly ranks the interaction strength between the unique adsorption sites of the particle. In this presentation, we demonstrate that the analysis can be extended to a large variety of material particles, surfaces, and adsorbates. We will also show that the electrostatic potential at the nuclei of metal atoms on material surfaces is a strong indicator of the metal site stability. The stability, in its turn, is known to scale with adsorption energies of reaction intermediates in catalysis. Accordingly, it is found that the nuclear electrostatic potential is a good descriptor for chemical surface interactions.