Theoretical Studies on Quasi-Diabatic Electronic Effects in Lithium Heavily-Doped Polyacetylene

Abstract

A quasi-diabatic crystal orbital (CO) theory earlier developed has been applied to lithium heavily-doped trans-polyacetylene (t-PA) to study quasi-diabatic electronic effects in a metallic state. It has been shown that the quasi-diabatic electronic structure largely changes from the adiabatic electronic structure. This change arises from the strong interaction of the crystal momentum coupling between carbon π and lithium canonical COs. The coupling also leads to occurrence of a large spin-density-wave (biradical character) in the quasidiabatic electronic state. The occurrence has been analyzed to be due to a large electron-electron repulsive interaction. The quasi-diabatic electronic structure has been discussed with a focus on the electron-electron repulsion.