Analytic Potential Energy Functions for Simulating Aluminum Nanoparticles

Abstract

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.

Phase Behavior of Elemental Aluminum Using Monte Carlo Simulations

“…Thus, the EMB potential reproduces the dimer binding energy very well with an error of only 0.01 eV. 5 . In contrast, the EAM potential which was fully optimized over the entire data set, including the dimer data, overbinds Al 2 by 0.38 eV.…”

“…4 Recently, some of us and coworkers 5 have presented analytical potential energy functions that were validated against density-functional theory (DFT) results for Al clusters and nanoparticles. At 0 K, an accurate potential function and a calculation of the zeropoint energy suffice to give a reasonably complete and accurate thermodynamic description of a cluster, nanoparticle, or solid, but at finite temperatures, the entropy is important in determining thermodynamic properties, and statistical mechanical methods must be employed.…”

Comparison of embedded atom method potentials for small aluminium cluster simulations

“…Table 3 give a binding energy per atom to within 2% of the experimental value and density to within 1%. Interestingly, the NP-B potential performed equally well as compared to the bulk-fitted potentials for the structural and energetic properties, because the training set included a range of cluster sizes as well as the bulk with different weightings [25]. However, while the CleriRosato and Streitz-Mintmire potentials showed good agreement with the experimental elastic constants, the Sutton-Chen and NP-B showed significantly larger variations.…”

“…2 for the EAM potentials considered in this study, along with the PBE/DNP and PBE0/MG3 levels, the latter of which was used in fitting the NP-B potential [25]. The PBE/DNP binding energy curve compares favourably to the PBE0/MG3 results, with a slightly slower decay of the potential beyond the equilibrium value.…”

“…) and bulk aluminium obtained by first principles methods [25,26]. In this work, we present a comparison of the structural and thermodynamical behaviour of a number of clusters of interest to our longer term research goals modelled using the Truhlar potential (NP-B) and three commonly used bulk-fitted EAM potentials [22,20,21].…”