Accession Number : ADA316044

Title :   Effective Medium Theory Characterization of Au/Ag Nanoalloy-Porous Alumina Composites.

Descriptive Note : Interim rept.,

Corporate Author : COLORADO STATE UNIV FORT COLLINS DEPT OF ANIMAL SCIENCE

Personal Author(s) : Hornyak, G. L. ; Patrissi, C. J. ; Martin, C. R. ; Valmalette, J. C. ; Lemaire, L.

PDF Url : ADA316044

Report Date : 30 SEP 1996

Pagination or Media Count : 9

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.

Descriptors :   *COMPOSITE MATERIALS, *SILVER ALLOYS, *ALUMINUM OXIDES, *POROUS MATERIALS, *GOLD ALLOYS, DATA BASES, OPTICAL PROPERTIES, SPHERES, TRANSMITTANCE, PURITY, PARTICLES, COLORS, ABSORPTION.

Subject Categories : Properties of Metals and Alloys
      Inorganic Chemistry
      Physical Chemistry
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE