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.
