Theoretical study of sulfur L-edge XANES of thiol protected gold nanoparticles

Abstract

The Scalar Relativistic-Zero Order Regular Approximation-Time Dependent Density Functional Theory has been employed to study the sulfur L-edge XANES spectrum of the [Au₂₅(SCH₃)₁₈]⁺ model cluster, with the aim to reproduce and rationalize previous experimental data. The salient experimental features are properly described by the present calculation. The model cluster contains two different types of bidentate “staple” ligand thiol fragments, and it has been possible to assign the spectral features according to the different location of the initial core orbital on one of the two different fragments. This finding suggests that in the real nanoparticle two different non-equivalent type of sulfur bidentate ligands are present, arranged with the typical staple geometry.