The recently proposedabinitioeffective Hamiltonian technique is extended to polymer calculations and applied to various conformations of polyacetylene (allhyphen;trans,cishyphen;transoid, andtranshyphen;cisoid) and polydiacetylene (acetylenic and butatrienic backbones). Band structures, density of states (DOS), and XPS theoretical spectra are presented. Comparison of the band structures and DOS with those obtained byabinitioSCF (selfhyphen;consistenthyphen;field) Hartreendash;Fock calculations of double zeta quality is excellent. The XPS theoretical spectrum for allhyphen;transpolyacetylene is in good agreement with experiment. In polyacetylene, it is found that the pgr; bands are quite similar for all three backbone conformations, though the sgr; bands differ significantly. For polydiacetylene, low ionization potentials are predictedmdash;a few tenths of an eV larger than polyacetylene for the acetylenic backbone and a few tenths of an eV smaller than polyacetylene for the butatrienic backbone.
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