Effective Medium Theory Characterization of Au/Ag Nanoalloy-Porous Alumina Composites.
Abstract
The optical constants n sub Al and k sub Al of a 50/50 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-alloy/insulator 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 60/40-70/30 volume fraction respectively) is needed to obtain the scarlet-red exhibited by the famous Lycurgus cup of 4th century Rome.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1996
- Accession Number
- ADA316044
Entities
People
- C. J. Patrissi
- C. R. Martin
- G. L. Hornyak
- J. C. Valmalette
- L. Lemaire
Organizations
- Colorado State University