STRUCTURAL AND ELECTRONIC-PROPERTIES OF POLYMERIC FULLERENE CHAINS

Properties of polymeric fullerenes are studied theoretically using a s emiempirical model that treats only the pi electrons explicitly but al lows for lattice relaxations. Both neutral and charged systems are stu died, and both the isolated C-60 molecule as well as the polymer. In a greement with experiments, the model predicts the elongation of certai n intraball bonds upon polymerization as the most significant structur al relaxation. This is found both for the neutral and the charged syst em. For the latter, we observe symmetry reductions, and it is suggeste d that polaronlike distortions or charge-density waves may act as char ge carriers. The distortions are predicted to induce extra phonon mode s that should be observable experimentally.