TY - JOUR
T1 - The colours of nanometric gold
T2 - OOptical response functions of selected gold-cluster thiolates
AU - Wyrwas, R. B.
AU - Alvarez, M. M.
AU - Khoury, J. T.
AU - Price, R. C.
AU - Schaaff, T. G.
AU - Whetten, R. L.
PY - 2007/7
Y1 - 2007/7
N2 - A set of broad-range NIR-vis-UV optical absorption spectra, measured for selected gold-cluster thiolate compounds (GCTs, containing ~20 to 300 Au atoms), is consistently displayed and then analyzed within the dielectric-functions approach. The size-evolution toward 'bulk' (Au diameter >3-nm) optical response is thereby clearly demonstrated. The emergence of apparent energy gaps, Eon, for onset of optical absorption, as well as other fine-structure, is consistent with that of a well-quantized metallic electronic structure for the compounds' cores: the onset-band's location Eon and intensity are attributed semiclassically to a circulation-frequency resonance of the Fermi-level electrons. With decreasing cluster-size, an increasing fraction of the integrated (sum-rule) intensity is 'missing' from the <4 eV region. This might be explained by the outermost layer consisting of Au(I)thiolate complexes.
AB - A set of broad-range NIR-vis-UV optical absorption spectra, measured for selected gold-cluster thiolate compounds (GCTs, containing ~20 to 300 Au atoms), is consistently displayed and then analyzed within the dielectric-functions approach. The size-evolution toward 'bulk' (Au diameter >3-nm) optical response is thereby clearly demonstrated. The emergence of apparent energy gaps, Eon, for onset of optical absorption, as well as other fine-structure, is consistent with that of a well-quantized metallic electronic structure for the compounds' cores: the onset-band's location Eon and intensity are attributed semiclassically to a circulation-frequency resonance of the Fermi-level electrons. With decreasing cluster-size, an increasing fraction of the integrated (sum-rule) intensity is 'missing' from the <4 eV region. This might be explained by the outermost layer consisting of Au(I)thiolate complexes.
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U2 - 10.1140/epjd/e2007-00117-6
DO - 10.1140/epjd/e2007-00117-6
M3 - Article
AN - SCOPUS:34249733012
SN - 1434-6060
VL - 43
SP - 91
EP - 95
JO - European Physical Journal D
JF - European Physical Journal D
IS - 1-3
ER -