Understanding the valence-band spectra of carbon fibers

Understanding the valence-band spectra of carbon fibers 

The calculated spectra of Fig. 18 indicate that two important pieces of information can be obtained from the valence-band spectra of carbon fibers  

The C-bridged structure referred to earlier is shown in Fig. I8d with a hydrogen atom placed symmetrically between two oxygen atoms. The C-O bond length u.sed (().I282. nm) was intermediate between that of-C=0 (0.1215 ran) and -C-OH (0.135 nm). The real situation may be more complex, probably with a double potential well, but the bridged . structure is regarded as a reasonable model for this type of oxidation. 

The ability of the valence-band region to provide more chemical infonnation than the core region is demonstrated by the author s work on the electrochemical oxidation of pitch-based fibers in ammonium carbonate solution 50. Both 

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