Li ionization potential

The XANES of carbonates have been studied by Madix et al. (1988), who observed a transition at 290 eV to an orbital they identified as 7T c o corresponding to the Za/ orbital in Fig. 5.25, about 1 eV above the C li ionization potential (Fig. 5.27 Tegeler et al., 1980). The carbon x-ray emission spectrum and XANES calculated for C(OH)j by Tossell (1986) are compared with experimental values in Table 5.12 and show reasonable agreement. Note that the previously calculated C Is ionization potential of Tossell (1986) was too high by almost 20 eV (306.4 versus 288.8 eV), leading to the erroneous conclusion that the C Is— XANES peak lay below the C Is ionization threshold. As observed in numerous other cases, the core ct resonance (C ls- 4e in this case) is sensitive to nearest-neighbor distance and is thus a measure of R(C-0). 

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