The electronic structure of the conjugated polymer, polyaniline, has been studied by resonant and nonresonant soft x-ray emission spectroscopy using synchrotron radiation for the excitation. The measurements were made on polyaniline and a few doped (protonated) phases for both the carbon and nitrogen contents. The resonant x-ray emission spectra show depletion of the π electron bands due to the selective excitation which enhances the effect of symmetry selection rules. The valence band structures in the x-ray emission spectra attributed to the π bands show unambiguous changes of the electronic structure upon protonation. By comparing to x-ray absorption measurements, the chemical bonding and electronic configuration is characterized.
Magnuson, M., Guo, J. H., Butorin, S. M., Agui, A., Såthe, C., Nordgren, J., & Monkman, A. P. (1999). The electronic structure of polyaniline and doped phases studied by soft x-ray absorption and emission spectroscopies. Journal of Chemical Physics, 111(10), 4756–4761. https://doi.org/10.1063/1.479238