Determination of plasma frequency, damping constant, and size distribution from the complex dielectric function of noble metal nanoparticles

Journal Article · Sun Dec 21 00:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4904349· OSTI ID:22402797

Mendoza Herrera, Luis J.; Arboleda, David Muñetón ^[1]; Schinca, Daniel C.

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1. Centro de Investigaciones Ópticas (CIOp), (CONICET La Plata-CIC) (Argentina)

This paper develops a novel method for simultaneously determining the plasma frequency ω{sub P}   and the damping constant γ{sub free} in the bulk damped oscillator Drude model, based on experimentally measured real and imaginary parts of the metal refractive index in the IR wavelength range, lifting the usual approximation that restricts frequency values to the UV-deep UV region. Our method was applied to gold, silver, and copper, improving the relative uncertainties in the final values for ω{sub p} (0.5%–1.6%) and for γ{sub free} (3%–8%), which are smaller than those reported in the literature. These small uncertainties in ω{sub p} and γ{sub free} determination yield a much better fit of the experimental complex dielectric function. For the case of nanoparticles (Nps), a series expansion of the Drude expression (which includes ω{sub p} and γ{sub free} determined using our method) enables size-dependent dielectric function to be written as the sum of three terms: the experimental bulk dielectric function plus two size corrective terms, one for free electron, and the other for bound-electron contributions. Finally, size distribution of nanometric and subnanometric gold Nps in colloidal suspension was determined through fitting its experimental optical extinction spectrum using Mie theory based on the previously determined dielectric function. Results are compared with size histogram obtained from Transmission Electron Microscopy (TEM)

• OSTI ID: 22402797
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
77 NANOSCIENCE AND NANOTECHNOLOGY
COPPER
DAMPING
DIELECTRIC MATERIALS
DISTRIBUTION
FUNCTIONS
GOLD
LANGMUIR FREQUENCY
NANOPARTICLES
NANOSTRUCTURES
OSCILLATORS
REFRACTIVE INDEX
SERIES EXPANSION
SILVER
SPECTRA
TRANSMISSION ELECTRON MICROSCOPY
WAVELENGTHS