First-principles calculations of circular dichroism of ligand-protected gold nanoparticles

Density functional theory calculations of the circular dichroism spectra of ligand-protected gold nanoclusters are performed to gain insight into the physical origin of their optical activity. The case of two different atomic models of the thiolated Au₃₈(SCH₃)₂₄ nanocluster is studied in detail, where the contribution to the circular dichroism spectra from the building parts of the nanoparticle, named core atoms, shell atoms, and ligand molecules, are analyzed separately. The results support the proposal of an intrinsically or ligand-induced chiral metallic core as the main responsible of their optical activity.