Effective Medium Theory Characterization of Au/Ag Nanoalloy-Porous Alumina Composites.
COLORADO STATE UNIV FORT COLLINS DEPT OF ANIMAL SCIENCE
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The optical constants n sub Al and k sub Al of a 5050 volume fraction Au Ag alloy were derived synthetically by application of a Bruggeman BG effective medium expression. The alloy data base was then input into a Maxwell-Garnett MG effective medium expression to determine the absorption maximum of the nano-alloyinsulator composite the volume fraction of the nano-alloy was equal to 5. The absorption maximum lambda max of the hypothetical composite was found to be 499 nm for spherical particles and was blue-shifted relative to that of a composite containing pure gold nanospheres 499 vs. 528 nm respectively. The transmission color at this wavelength was a red-orange. lambda max in the range 512 to 519 nm Au Ag alloy between 6040-7030 volume fraction respectively is needed to obtain the scarlet-red exhibited by the famous Lycurgus cup of 4th century Rome.
- Properties of Metals and Alloys
- Inorganic Chemistry
- Physical Chemistry