D.A. Shirley

Photoemission from solids: the transition from solid-state to atomic physics

Interactions between solid-state and atomic physics are potentially very valuable, yet little studied as yet. Nowhere is this more true than in photoelectron spectroscopy, which has been developed quite independently in its applications to atomic and solid-state physics. In recent years, however, several phenomena attending photoemission have been specifically addressed in relation to their occurrence in both atoms and solids. Kunz and co-workers at DESY have compared total absorption in atoms and condensed phases, finding strong similarities and interesting differences. Focussing more explicitly on core-level photoemission per se, two groups at SSRL—Lindau, Spicer, et al., and our own—have found that total photoelectric cross-sections of core electrons in solids show interesting atomic behavior, including Cooper minima. Figure 1 illustrates this behavior.1–3