Structure factor in photoemission from valence band

Two-dimensional angular distribution of photoelectrons from valence band was analyzed using a tight-binding initial state. In simple cases, the angular distribution call be understood as a product of ''one-dimensional density of states(ODDOS)'', ''photoemission structure factor'', and ''angular distribution from atomic orbital''. This newly introduced ''photoemission structure factor'' is an intensity distribution in a reciprocal space similar to the X-ray or electron diffraction structure factor replacing scattering factor by the coefficient for each. atomic orbital in the LCAO wavefunction. The remarkable symmetry-broken patterns observed from pi band of single-crystalline graphite was clearly explained. The two-fold symmetry was obvious as the result of the ''angular distribution from the P-z atomic orbital'' for the s- and linearly-polarized synchrotron radiation. The difference of the intensity in different BZs was clearly explained by the photoemission structure factor. Hence, the two-dimensional measurement call give us information not only (1) about the ODDOS, but also (2) about the symmetry of the initial state, and even more (3) about the coefficients in the initial state wavefunction.