Analytic potential energy functions for simulating aluminum nanoparticles

Potential energy functions (PEFs) parametrized to bulk data are shown to perform poorly for small aluminum nanoparticles and clusters. In contrast, PEFs parametrized to a limited set of cluster and bulk data, but no nanoparticle data, perform well for nanoparticles. This validates a practical scheme for developing PEFs for nanoscale systems. Building on these findings, we optimized five PEFs by minimizing the error in the fit over a broad data set. Two of these PEFs have errors of less than or equal to 0.08 eV/atom for each of three categories of system sizes, i.e., for small clusters, for nanoparticles, and for bulk potential energies.