Study of the electronic structure of short chain oligothiophenes.
The electronic structure of short-chain thiophenes (thiophene, 2,2'-bithiophene, and 2,2':5',2″-terthiophene) in the gas phase has been investigated by combining the outcomes of Near-Edge X-ray-Absorption Fine-Structure (NEXAFS) and X-ray Photoemission Spectroscopy (XPS) at the C K-edge with those of density functional theory (DFT) calculations. The calculated NEXAFS spectra provide a comprehensive description of the main experimental features and allow their attribution. The evolution of the C1s NEXAFS spectral features is analyzed as a function of the number of thiophene rings; a tendency to stabilization for increasing chain length is found. The computation of the binding energy allows to assign the experimental XPS peaks to the different carbon sites on the basis of both the inductive effects generated by the presence of the S atom as well as of the differential aromaticity effects.
Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste, Italy.
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0000000262552041
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Grazioli
Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste, Italy.
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Baseggio
Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste, Italy.
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0000000337007903
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Stener
Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste, Italy.
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Fronzoni
CNR-IOM, Laboratorio TASC, Sincrotrone Trieste, I-34149 Trieste, Basovizza, Italy.
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0000000294910173
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de Simone
CNR-ISM, Sincrotrone Trieste, I-34149 Trieste, Basovizza, Italy.
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000000034376808X
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Coreno
CNR-ISM, Tito Scalo, C/da S. Loja, 85050 Tito Scalo, Potenza, Italy.
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Guarnaccio
CNR-ISM, Tito Scalo, C/da S. Loja, 85050 Tito Scalo, Potenza, Italy.
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Santagata
Science Department, University of Basilicata, 85100 Potenza, Italy.
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D'Auria