@conference {19637, title = {Geometry and Charge State of Mixed-Ligand Au13 Nanoclusters}, booktitle = {X-RAY ABSORPTION FINE STRUCTURE - XAFS13: 13th International Conference}, volume = {882}, year = {2007}, month = {2007/02/02/}, pages = {749 - 751}, publisher = {AIP Publishing}, organization = {AIP Publishing}, abstract = {The integration of synthetic, experimental and theoretical tools into a self-consistent data analysis methodology allowed us to develop unique new levels of detail in nanoparticle characterization. We describe our methods using an example of Au 13 monolayer-protected clusters (MPCs), synthesized by ligand exchange methods. The combination of atom counting methods of scanning transmission electron microscopy and Au L3-edge EXAFS allowed us to characterize these clusters as icosahedral, with surface strain reduced from 5\% (as in ideal, regular icosahedra) to 3\%, due to the interaction with ligands. Charge transfer from Au to the thiol and phosphine ligands was evidenced by S and P K-edge XANES. A comparison of total energies of bare clusters of different geometries was performed by equivalent crystal theory calculations.}, keywords = {Atom surface interactions, Charge transfer, Data analysis, Extended X-ray absorption fine structure spectroscopy, Gold, nanoparticles, Scanning transmission electron microscopy, Surface strains, Total energy calculations, X-ray absorption near edge structure}, url = {http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.2644652}, author = {Frenkel, A. I. and Menard, L. D. and Northrup, P. and Rodriguez, J. A. and Zypman, F. and Dana Dachman-Soled and Gao, S.-P. and Xu, H. and Yang, J. C. and Nuzzo, R. G.} }