posted on 2013-10-10, 00:00authored byAlfredo Tlahuice-Flores, Ulises Santiago, Daniel Bahena, Ekaterina Vinogradova, Cecil V. Conroy, Tarushee Ahuja, Stephan
B. H. Bach, Arturo Ponce, Gangli Wang, Miguel José-Yacamán, Robert L. Whetten
The
structure of the recently discovered Au130-thiolate
and -dithiolate clusters is explored in a combined experiment-theory
approach. Rapid electron diffraction in scanning/transmission electron
microscopy (STEM) enables atomic-resolution imaging of the gold core
and the comparison with density functional theory (DFT)-optimized
realistic structure models. The results are consistent with a 105-atom
truncated-decahedral core protected by 25 short staple motifs, incorporating
disulfide bridges linking the dithiolate ligands. The optimized structure
also accounts, via time-dependent DFT (TD-DFT) simulation, for the
distinctive optical absorption spectrum, and rationalizes the special
stability underlying the selective formation of the Au130 cluster in high yield. The structure is distinct from, yet shares
some features with, each of the known Au102 and Au144/Au146 systems.