  The optical spectra of CeO2 have been systematically investigated using three
first-principles computational approaches for comparison, namely, the
Heyd-Scuseria-Ernzerhof (HSE) screened hybrid functional, HSE+\emph{U}, and
\emph{GW}+\emph{U}. Our results show that by using the HSE+\emph{U} method, the
calculated electronic structures are in good agreement with experimental
spectra and the resulting imaginary part of the optical dielectric function
spectrum well reproduces the main features exhibited in experimental
observations. The important adsorption spectrum and energy loss function also
accord well with the experimental results.
