Optical Constants of YVO4 Between 2 and 25 eV

摘要

The optical constants of YVO4 have been determined from 1.96 to 25 eV. In the region of high transparency, from 1.76 to 3.7 eV, the refractive index was determined from prism refraction measurement. Near‐normal‐incidence reflectivity measurements were made from the absorption threshold to 25 eV. These data were extrapolated to zero and to infinite frequency and the optical constants were obtained from a Kramers‐Kronig inversion. Our spectra are in good agreement with the predictions of Walter and Butler. The complex dielectric function, ϵ1+iϵ2, was approximated by a simple Lorentzian oscillator model and it was found that the optical spectra from 2 to 25 eV can be attributed to only 24 electrons per YVO4 molecule. The same result is obtained from sum rule computations on ϵ2 and -Im 1/ϵ out to 200 eV, using the extrapolated results. The maximum in the loss function, -Im 1/ϵ occurs at 23 eV.