XANES INVESTIGATION OF CHEMICAL-STATES OF NITROGEN IN POLYANILINE

X-ray absorption and photoelectron spectra of polyaniline were investi gated in order to characterize the chemical bonding of its nitrogen at oms. The identification of neutral and charged nitrogen groups is of s pecial interest. X-ray absorption near-edge structure (XANES) at the n itrogen K edge shows characteristic resonance structures reflecting tr ansitions from the N1s core-level into unoccupied states. For comparis on N1s X-ray photoelectron spectra were recorded representing the init ial state of the N1s(-1)2p(pi/sigma*) transitions. Due to the increas ing energy differences between the N1s initial state and the unoccupie d pi and sigma states, discrete final states, originating from the dif ferent chemical bonding at the nitrogen atom (=N-,=NH+-and-NH -), were resolved in the N K XANES. (C) 1998 Elsevier Science S.A.