Insulator-Metal Transition intrans-Polyacetylene

Optical and energy-loss data suggest that the soliton lattice, which accounts for the low Pauli susceptibility χP at average doping concentrations 〈y〉<4% to 6%, persists to higher $〈y〉$. We have calculated the eigenvalues for a trans-polyacetylene chain with the electrons in soliton states for the geometry and y values appropriate to metallic Na-doped polyacetylene and the Coulomb potential of the ions and solitons on other chains included. We find that, allowing for chains {} 100 C-H units in length, we can account for χP in the metallic state.