GIANT TEMPERATURE EFFECTS IN NORMAL-EMISSION PHOTOELECTRON-SPECTRA FROM AG(111) AND AU(111)

The experimental determination of electronic energy bands E(k) from th e kinematical analysis of angle-resolved photoelectron spectra is now nearly routine. In contrast only very few attempts have been made to q uantitatively interpret peak intensities (going beyond the application of polarization selection rules), In this context we did investigate the influence of temperature T on peak intensities and linewidths, Dur ing that work we detected that at particular k-space points bulk direc t transition intensities exhibit a ''giant'' T dependence, with temper ature coefficients larger by an order of magnitude as compared to othe r k-space points nearby. We present such data and compare them to calc ulations performed within the one-step theory of photoemission. An int erpretation is given by multiple scattering effects and a constructive final state interference.