Metal/conjugated polymer interfaces: Sodium, magnesium, aluminum, and calcium on trans-polyacetylene.

Quantum chemical calculations are performed to theoretically study the interaction between low work function metal atoms and trans-tetradecaheptaene, an extended model molecule for π-conjugated polymers. We present characterizations of metal/polyene complexes obtained by the local spin density method. The results show that charge transfer reactions occur for Na and Ca and the formation of a covalent bond for Al. Mg atoms, however, are found not to react significantly with π-conjugated systems. Differences in the bonding mechanism between the metals are discussed and the theoretical density of valence states are compared to experimental photoelectron spectroscopy (UPS) data. The results demonstrate that the local spin density method can be successfully used to interpret valence UPS spectra from early stages of metal/π-conjugated interface formation. [ABSTRACT FROM AUTHOR]