New challenges in computational quantum chemistry : dedicated to prof. dr. W.C. Nieuwpoort on the occasion of his twenty-fifth anniversary as a professor in Theoretical Chemistry at the University of Groningen / edited by R. Broer, P.J.C. Aerts, P.S. BagusImpactRelativity, correlation and core electron spectra / Rob KloosterRelativity, correlation and core electron spectra / Rob KloosterQuantum chemical studies of the physics around the metal-insulator transition in (EDO-TTF)2PF6 / Gerrit-Jan Linker