Synchrotron radiation soft x-ray photoemission spectroscopy was used to directly observe Se3dcore-level binding energy shifts from surface atoms of the (100) face of epitaxialCuInSe2/ GaAs(100). High-resolution spectra show two sets of Se3d5/2,3/2spin-orbit components separated by 0.6 eV, with the low-binding-energy peaks being associated with the surface atoms. However, surface state emission from Sepstates in the valence band was not observed due to the low photoionization cross sections. Cation bonding-antibonding states were observed in the valence band and are centered at about 1.0 and 3.1 eV below the valence band edge. ©1997 American Institute of Physics.