Counting the atoms in supported, monolayer-protected gold clusters.
Mass spectrometry of supported, monolayer-protected, nominally Au(38) (MP-Au(38)) clusters is performed via quantitative High Angle Annular Dark Field-Scanning Transmission Electron Microscopy (HAADF-STEM) using size-selected Au(N) clusters (N = 25, 38, 55) as mass standards. With the intensity due to the (presumed) 24 hexanethiolate ligands taken into account, the clusters are found to contain 38 +/- 2 Au atoms. The method may also be used to determine the degree of aggregation of deposited nanoparticles.
Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, United Kingdom.
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Wang
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Toikkanen
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Yin
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Li
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Quinn
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Palmer