EXAFS investigations on highly-ordered ultrathin films of Me-DCNQI on single crystal surfaces

DMe-DCNQI forms highly-ordered ultrathin films on various single crystal surfaces. NEXAFS reveals flat lying molecules for all investigated film thicknesses (up to 40 layers) on nearly all substrates under investigation (Ag(111), Ag(100), Cu(100), Cu(111)). The C1s and N1s NEXAFS spectra of these condensed layers show several very sharp resonances. The comparison with the quinoide molecules TCNQ and DMe-BQ shows similarities, but the electronic structure is too complicated to be interpreted in terms of a building block scheme. NEXAFS data of related charge transfer salts consist of fewer and much broader resonances in accordance with the more delocalized electronic structure of the 'quasimetallic' salts.