| Abstract
| - We report on C 1s and N 1s near-edge X-ray absorption (NEXAFS) investigations of highly orientedultrathin films of 2,5-dimethyl-N,N‘-dicyanoquinonediimine (DMe-DCNQI), tetracyano-quinonedimethane(TCNQ), and 2,5-dimethyl-1,4-benzoquinone (DMe-BQ) adsorbed on Ag(111). Several sharp resonancesare resolved in the spectra indicating the localized electronic structure of these quinoide molecules. Thecomparison of the angle-dependent DMe-DCNQI results with those from other molecules and literaturedata on cyano-containing molecules leads to the conclusion that the common building-block approach isnot sufficient, but that the interpretation of most valence orbitals being delocalized within the wholemolecule appears to be more appropriate as confirmed by semiempirical INDO/S SDCI calculations. TheNEXAFS spectra of the related DMe-DCNQI charge transfer salts also reflect strongly delocalized molecularorbitals very different from those of unreacted DCNQI.
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