Lattice Vibrations of V2O5. Determination of TO and LO Frequencies from Infrared Reflection and Transmission

The reflectance of V2O5, single crystals is measured between 20 and 2000 cm−1. Eleven resonances are observed: six with E ∥ a, two with E ∥ b, and three with E ∥ c. Values of ϵ0 are obtained separately from thin crystal channel spectra: ϵ0 = 37.2 with E ∥ a and 20.1 with E ∥ c. The reflectance data are analysed by Kramers‐Kronig integration, classical dispersion analysis, and four‐parameter dispersion analysis, all three methods yielding comparable results. Additional transmission measurements of thin single crystals and powders are performed. For the thin single crystal, absorption peaks at 982 and 1038 cm−1 are observed which are assigned to direct absorption of a TO and a LO vibration.