A theoretical quantum study on the distribution of electrophilic and nucleophilic active sites on the Au(100) surface modeled as finite clusters

Abstract

A theoretical quantum study on the distribution of active sites on gold surfaces with (100) orientation is reported. Gold surfaces were modeled by finite clusters, keeping the face centered cubic crystal symmetry and net parameters. We define an electronic unit cell (EUC) as the minimal cluster's size that allows one to reproduce some electronic properties of the macroscopic surface. These were computed at an ab initio Hartree–Fock LANL1MB pseudopotentials level with an ONIOM-like space partition method. We validated our model comparing the work function (∼5.0 eV), band gap (∼2.45 eV) and density of states calculated in this work, with those values reported in literature. Using the concept of EUC, it was possible to suggest a qualitative macroscopic distribution of active sites on the macroscopic gold surface (100). We found that the electrophilic and nucleophilic active sites for this surface are preferably located on hollow positions and their density number is 1.6×10 14 sites/cm 2 in both cases.