  We obtained the spectral function of very high quality natural graphite
single crystals using angle resolved photoelectron spectroscopy (ARPES). A
clear separation of non-bonding and bonding bands and asymmetric lineshape are
observed. The asymmetric lineshapes are well accounted for by the finite
photoelectron escape depth and the band structure. The extracted width of the
spectral function (inverse of the photohole life time) near the K point is,
beyond the maximum phonon energy, approximately proportional to the energy as
expected from the linear density of states near the Fermi energy. The upper
bound for the electron-phonon coupling constant is about 0.2, a much smaller
value than the previously reported one.
