Electrostatic fields above individual atoms

This review describes recent field ion microscopic measurements of local electrostatic fields in the immediate vicinity of individual surface atoms. The studies were stimulated and supported by self-consistent theoretical calculations on the field distribution close to single atoms of different electronic structure adsorbed on a metal surface in the presence of high external fields. The experimental and theoretical data establish the existence of strongly varying local field distributions above different surface atoms. New details concerning localized field ionization and image formation processes occurring in the field ion microscope are revealed.