Excitonic optical spectrum of semiconductors obtained by time-dependent   density-functional theory with the exact-exchange kernel
  Applying the novel exact-exchange (EXX) Kohn-Sham method within time-dependent density-functional theory, we obtained the optical absorption spectrum of bulk silicon in good agreement with experiments including excitonic features. Analysis of the EXX kernel shows that inclusion of the Coulomb coupling of electron-hole pairs and the correct long-wavelength behavior in the kernel is crucial for the proper description of excitonic effects in semiconductors. 
Yong-Hoon Kim and Andreas Goerling