Issues

Progress in picturing the distribution of electrons in the outer few atomic layers encourages our efforts to understand how surfaces interact with the outside world.

Various experimental techniques show that atoms adsorbed onto a crystal surface form two‐dimensional arrays with a structure that depends on their density, the temperature and the substrate.

Studies of intrinsic surface states and of absorbate surface states, both at ultraviolet and x‐ray photon energies, are among the many applications of this versatile probe.

Many methods are available whereby transitions involving core electrons reveal the identities of atoms in the surface region and their local electronic environments.

The extension into the vacuum of the exponential tail of the wave function makes possible remarkably sensitive techniques based on field emission, ion neutralization and field ionization.