Short-Range Order Full Multiple Scattering Approach to the Polarized K-Edge XANES of Br Doped in Trans-Polyacetylene

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Abstract
In this work, we have analysed the Br K -edge XANES of (CHBr y ) x excited by polarized X-ray in // c and ⊥ c directions for three different doping region. In the low doping region it is proved that mono-anions exist, and the information about the charge distribution on carbon chains around the mono-anions is obtained. The maximal amplitude of the charge density is larger than 0.4. In the intermediate doping region ( y =0.0145), the XANES analyses also confirm the model previously proposed by Oyanagi et al. , in which polyanions Br 3 - and covalently bonded bromine atoms coexist. From the analysis of E // c XANES, it is concluded that Br 3 - has larger polarization approximately shown by Br -0.6 Br -0.2 Br -0.6 than I 3 - by I -0.5 I 0.0 I -0.5 . In the high doping region, there are many possible models more than 10 6 . In this case the detailed analyses would be impossible.