Abstract
The optical constant of bulk metal is used to determine the dispersion of the local field under one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) confinement. 3D confinement, expressed as ε 2 m i c ( ω 3 D ) , corresponds to the dielectric loss spectra of spherical particles with a diameter, d, much less than the wavelength of the beam used to measure the spectrum (d << λ). Excellent agreement with the results of Mie theory and experimental data for solid colloids within alkali halide crystals was observed. The function expressed as ε 2 m i c ( ω 1 D ) allows the measurement of spectral micro-characteristics in the frequency range of the longitudinal collective motion of the free electrons. This corresponds to the spectrum of dielectric losses of bulk plasma oscillations. The function ε 2 m i c ( ω 2 D ) describes the spectra of the dielectric losses of surface plasma oscillations in thin metal films. It is shown that the peak positions of ε 2 m i c ( ω 3 D ) , ε 2 m i c ( ω 2 D ) and ε 2 m i c ( ω 1 D ) spectra for simple metals, viz. alkali metals as well as Al, Be, Mg, Ga, In, Sn and Si, are in agreement with experimental results from electron-energy-loss spectroscopy and various optical techniques.