ON THE HISTORY OF PHOTOEMISSION

While field emission proves to be the oldest surface science, photoemission is certainly one of its most important branches. We will describe, in some detail, the early development of this field from the scarcely understood photoelectric observations to the commonly accepted and applied photoemission process, in the course of which very important fundamental physical discoveries were involved. Since the early sixties, research contributions have multiplied and photoemission spectroscopy has become a major investigative technique in solid state and surface physics as well as chemistry. Because of its recent rapid growth, the latter aspect is only discussed in the final overview.