ANGLE-RESOLVED PHOTOEMISSION EXTENDED FINE-STRUCTURE - MULTIPLE LAYERS OF EMITTERS AND MULTIPLE INITIAL STATES

Recently, angle-resolved photoemission extended fine structure (ARPEFS ) has been applied to experimental systems involving multiple layers o f emitters and non-s core-level photoemission in an effort to broaden the utility of the technique. Most of the previous systems have been c omprised of atomic or molecular overlayers adsorbed onto a single-crys tal, metal surface and the photoemission data were taken from an s ato mic core-level in the overlayer. For such a system, the acquired ARPEF S data is dominated by the p(0) final state wave backscattering from t he substrate atoms and is well understood. In this study, we investiga te ARPEFS as a surface-region structure determination technique when a pplied to experimental systems comprised of multiple layers of photoem itters and arbitrary initial state core-level photoemission. Understan ding the data acquired from multiple layers of photoemitters is useful for studying multilayer interfaces, ''buried'' surfaces, and clean cr ystals in ultra-high vacuum. The ability to apply ARPEFS to arbitrary initial state core-level photoemission obviously opens up many systems to analysis. Efforts have been ongoing to understand such data in dep th. We present clean Cu(111) 3s, 3p, and 3d core-level, normal photoem ission data taken on a high resolution soft x-ray beamline 9.3.2 at th e Advanced Light Source in Berkeley, California and clean Ni(111) 3p n ormal photoemission data taken at the National Synchrotron Light Sourc e in Upton, New York, USA.