Quantum chemical studies on intercalation of lithium into polyacene

The structure and properties of Li-doped polyacenic semiconductor (PAS) mat erial have been investigated. Quantum Chemical methods ab initio STO-3G wer e used to calculate electronic properties of PAS doped with lithium. The se miempirical MO method AMI was used to optimize the geometric parameters of PAS. The theoretical results showed that the doped lithium was neither in m etallic nor ionic stale in deeply doped PAS (C2Li). The intercalated lithiu m formed polycenter bonds with carbon atoms, and made the interlayer distan ce of two parallel polyacenic rings decrease. On the other hand, the total energy of Li-doped PAS system decreased, and made the doped state stable. T he theoretical results are in good agreements with the experiment.