Observations on the photoelectric work function and leed pattern from the (111) surface of an iron single crystal

Abstract The photoelectric work function and atomic configuration of α-iron (111) surfaces have been studied by the Fowler method and by low-energy electron diffraction (LEED) respectively under identical condition in ultra-high vacuum. The LEED pattern indicated that the atomically clean iron (111) surface was an unreconstructed surface. The photoelectric work function of the clean iron (111) surface was 4.81 eV. The experimental error is ± 0.02 eV. When the clean surface was exposed to 1 × 10 −1 Torr·min of residual gases in the vacuum vessel, the work function of the clean iron (111) surface fell to 4.31 eV. Changes of photoelectric yield are measured against the residual gas exposure. The photoelectric current increases suddenly and soon saturates at a particular exposure condition. Some changes in work function have taken place with no observed change in the LEED pattern.