Observation of a surface chemical shift in carbon 1s core-level photoemission from highly oriented pyrolytic graphite -: art. no. 245409

Contributions to the line shape of high-resolution Al Kalpha x-ray excited carbon 1s photoemission of highly oriented pyrolytic graphite are described and compared with previous work. A two-component system is used to model experimental results obtained from two photoelectron takeoff angles. The splitting between the two components is 0.47+/-0.02 eV, with a variation in the intensity ratio consistent with that expected for the two takeoff angles. The photoemission lines are found to have a lifetime broadening Gamma(L) of 0.128+/-0.006 eV full width at half maximum (FWHM), an asymmetry alpha of 0.125+/-0.002, and additional broadening over that of the instrumental resolution of 0.28+/-0.04 eV FWHM.