Polarized infrared reflectance spectra of single crystal α-Bi2O3

Abstract

Polarized IR reflectance spectra of monoclinic single crystal α-Bi2O3 for different directions of the wave vectork and the electric fieldE of the incident radiation have been measured in a wide temperature range (25–400 K). A significant dependence of the spectrum shape on the direction of the vectorE within the ac-plane was observed. Frequencies, strengths, widths and polarizations of the TO modes were restored using the Lorentz dispersion model extended for the monoclinic crystal lattice. Remarkable distinction between intensities of Au- and Bu-modes is observed.