Analysis of XPS and XES of diamond and graphite by DFT calculations using model molecules

X-ray photoelectron and emission spectra (XPS and XES) of diamond and graph ite have been analyzed by deMon density-functional theory (DFT) calculation s using the model adamantane derivative (C10H12(CH3)(4)) and pyrene (C16H10 ) molecules, respectively. The theoretical valence photoelectron and C K al pha X-ray emission spectra for the allotrope are in good accordance with th e experimental ones. The combined analysis of the valence XPS and C K alpha XES enables us to divide the valence electronic distribution into the indi vidual contributions for p sigma-, and p pi -bonding MOs of the diamond and graphite, respectively. (C) 2000 John Wiley & Sons, Inc.