Localized hole pair states on a one dimensional linear chain: Magnus green salt

Abstract

The hole pair ground state of a 20 atom linear tight binding chain and the excitation energy to the first excited hole pair state have been calculated for several configurations of two halide ions. Except for a small number of configurations, the ground state has been generally found to exhibit greater delocalization along the chain than the single hole state and an excitation energy to the first excited state that is less than the excitation energy for the single hole. These results These results are consistent with the observation that the activation energy for conduction in the doped ’’one dimensional’’ compound Magnus green salt appears to shift to lower energy as the dopant level is increased. They also provide a glimpse into the initial stages of the formation of extended hole orbitals that could lead to the formation of a one dimensional metallic state at higher dopant levels.