Carlos Cardenas

Conceptual Density Functional Theory (cDFT) provides a rigorous framework to rationalize chemical reactivity through density-based response functions. Its extension to solids, however, is hindered by formal and computational challenges associated with periodic boundary conditions and charged systems. Here, we further develop cDFT descriptors for extended systems, focusing on the Fukui function and its associated electrostatic potential. We analyze different strategies to compute these quantities in solids, highlighting the impact of compensating background charges and electronic relaxation. By introducing practical correction schemes, we obtain physically meaningful Fukui functions and Fukui potentials for metallic and semiconducting surfaces. These descriptors consistently identify reactive regions and capture trends in surface reactivity. Crucially, we show that these quantities can be embedded within a cDFT perturbation theory framework to predict interaction energies between atomic species and surfaces. The resulting model separates electrostatic and charge-transfer contributions, enabling the estimation of adsorption trends without explicit total-energy calculations. Applications to prototypical surfaces reproduce the ordering of interaction energies for reducing and oxidizing species, demonstrating predictive capability. These results establish cDFT as a predictive framework for surface chemistry, bridging chemical bonding concepts and materials modeling.