X-ray photoelectron spectroscopy of brominated (SN)_x and S₄N₄

XPS spectra of thin films, prepared by the in situ bromination of (SN)_X and S₄N₄, have been recorded. The spectra obtained from brominated (SN)_X and S₄N₄ are essentially the same, indicating that the brominated polymer of the same structure is formed in both cases. The data in the valence band region show that the 4.2, 7.6 and 23.5 eV peaks of normal (SN)_X shift to higher binding energies on bromination. The bromine lines have single lorentzian lineshapes and correspond closely in binding energies to that of the Br^- ion in NaBr and CsBr. However, in brominated (SN)_X and S₄ N₄ films, the Br 4s level line has an anomalously high intensity relative to the Br 4p level emission. This indicates the likelihood of some bonding between bromine and the SN chain in the brominated polymer.