Excitonic effects in optical absorption and electron-energy loss spectra of hexagonal boron nitride

The work was supported by the EU network of excellence NANOQUANTA (NMP4-CT-2004-500198) and the French GDR "nanotubes". Calculations were performed at IDRIS (Project No. 51827) and CEPBA. A.R. acknowledges the Humboldt Foundation under the Bessel research award (2005).