Resonant photoemission and chemisorption studies of Tl‐Ba‐Ca‐Cu‐O

Resonant photoemission has been used to study the electronic states and electron‐electron interactions in a bulk sample of Tl‐Ba‐Ca‐Cu‐O high temperature superconductor. The electronic structure, i.e., broad peaks in the valence band at 3.2 and 5.5 eV and satellites at 10 and 13 eV binding energy, is similar to that observed for the 1‐2‐3 materials. This indicates that the electronic states and interactions are similar in these different classes of superconductor.The surface reactivity has been probed with photoemission using controlled exposures of atmospheric gases. Both H2O and CO2 react with a sticking probability of near 0.2, forming hydroxide, and carbonate species, respectively. O2 is non‐reacting while CO reacts only slightly.