POLYIODIDE CHAINS IN CRYSTALLINE ORGANIC IODIDES - AB-INITIO HARTREE-FOCK CRYSTAL ORBITAL STUDY

Hartree-Fock crystal orbital calculations of two crystalline organic i odides, tetrathiafulvalenium triiodide (TTFI-3) and dipyridinium deca iodide (NHC5H5)(2) I-10, were carried out. The former crystal contain s no true polyiodide chains, whereas such chains are present in the la tter crystal. In such a way, the effect of the polyiodide chain format ion on the electronic structure of crystalline organic iodides was stu died. The present calculations show that crystalline organic iodides w ith polyiodide chains could, in principle, be quasi-one-dimensional se miconductors. A polyiodide chain could be a carrier of semiconductivit y only when it is formed by fully charged iodide anions (no charge tra nsfer from the chain). (C) 1997 John Wiley & Sons, Inc.