  We perform first-principles calculations of electronic structure and optical
properties for UO2 and PuO2 based on the density functional theory using the
generalized gradient approximation (GGA)+\emph{U} scheme. The main features in
orbital-resolved partial density of states for occupied \emph{f} and \emph{p}
orbitals, unoccupied \emph{d} orbitals, and related gaps are well reproduced
compared to experimental observations. Based on the satisfactory ground-state
electronic structure calculations, the dynamical dielectric function and
related optical spectra, i.e., the reflectivity, adsorption coefficient,
energy-loss, and refractive index spectrum, are obtained. These results are
consistent well with the attainable experiments.
