Accession Number:

ADA275378

Title:

Template Synthesized Nanoscopic Gold Particles: Optical Spectra and the Effects of Particle Size and Shape

Descriptive Note:

Interim rept.

Corporate Author:

COLORADO STATE UNIV FORT COLLINS DEPT OF CHEMISTRY

Report Date:

1994-01-25

Pagination or Media Count:

44.0

Abstract:

We have prepared nanoscopic gold cylinders of controlled radius and aspect ratio via electrodeposition of the metal within the pores of anodically- grown porous aluminum oxide membranes. The nanocylinder radii are determined by the pore dimensions of the host alumina which, in turn, depend on anodization conditions. The particle aspect ratios were controlled by varying the amount of Au deposited within the pores The optical spectra of the gold nanocylinder alumina composites exhibit strong absorption bands in the visible spectrum. The extinction maxima Lambda max values for gold particles approaching sphere-like geometry agree well with Mie Theory calculations. The blue shift of Lambda max as the particle aspect ratio is increased is in qualitative agreement with Maxwell-Garnett Theory. We propose a simple modification of Maxwell-Garnett Theory that addresses both size and shape effects. Nanometals, Nanomaterials, Maxwell-Garnett theory.

Subject Categories:

  • Physical Chemistry
  • Laminates and Composite Materials
  • Electricity and Magnetism
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE