WANNIER-FUNCTION-BASED AB-INITIO HARTREE-FOCK APPROACH EXTENDED TO POLYMERS - APPLICATIONS TO THE LIH CHAIN AND TRANS-POLYACETLYLENE

A recently proposed ab initio Hartree-Fock approach aimed at directly obtaining the Wannier functions of a crystalline insulator is applied to polymers. The systems considered are the UH chain and trans-polyace tylene. In addition to being the first application of our approach to one-dimensional systems, this work also demonstrates its applicability to covalent systems. Both minimal as well as extended basis sets were employed in the present study and excellent agreement was obtained wi th the Bloch orbital based approaches. Cohesive energies, optimized la ttice parameters, and the band structure are presented. Localization c haracteristics of the Wannier functions are also discussed.