Electric potential energy of the incident light and the Hamiltonian of the induced oscillators in non-absorbing isotropic dielectrics

By considering an energy balance between the electric potential energy of the incident light and the Hamiltonian of the induced oscillators in a non-absorbing isotropic medium, the Newton-Drude equation, the Sellmeier dispersion formula, and the wavelength-dependent mean polarizability were derived. The Newton-Drude formula and the Lorentz-Lorenz equation were used to calculate the density-dependent mean polarizability of the densified silica glasses. The evaluated mean polarizability was compared with the band shifts in the UV- and IR-spectra with the density of glasses, and the validity of the Newton-Drude formula was discussed. (C) 1999 Elsevier Science B.V. All rights reserved.