Both XPS core level and valence band spectra were obtained from Du Pont E-75 pitch-based carbon fiber surface. The XPS data showed that the E-75 fiber had more oxygen content on the surface than the Du Pont higher modulus pitch-based carbon fiber (E-120), but less than the lower modulus pitch-based carbon fibers (Amoco P55X fiber and Du Pont E-35 fiber) and the PAN-based carbon fibers (Hercules AU4 and AS4). [See Y. Xie and P. M. A. Sherwood, Appl. Spectrosc.43, 1153 (1989); Chem. Mater.1, 427 (1989);2, 293 (1990); Appl. Spectrosc.44, 797 (1990); Chem. Mater.3, 164 (1991); Appl. Spectrosc.44, 1621 (1990);45, 1158 (1991); Y. Xie, T. Wang, O. Franklin, and P. M. A. Sherwood,ibid.46, 645 (1992).] The E-75 fiber also had a graphitic structure in both the surface and the bulk as evidenced by both XPS and XRD. No nitrogen was found on this E-75 fiber and other pitch-based carbon fiber surfaces, but it was found on PAN-based fibers. Our previously reported work [Y. Xie and P. M. A. Sherwood, Chem. Mater.1, 427 (1989);2, 293 (1990); Appl. Spectrosc.44, 797 (1990); Chem. Mater.3, 164 (1991); Appl. Spectrosc.44, 1621 (1990);45, 1158 (1991); Y. Xie, T. Wang, O. Franklin, and P. M. A. Sherwood,ibid.46, 645 (1992)], showed that XPS valence band spectra were more sensitive to chemical environment on the carbon fiber surface than core level spectra and could be well interpreted by X–αcalculations with model compounds.