Field Ion Microscopy

The basic physical effects used in field ion microscopy are not yet fully understood. Field evaporation rates of tungsten were measured in the range from 0.01 to 10,000,000 atomic layers/sec, yielding the polarizability of a kink site surface atom, the activation energy and the pre-exponential of the field evaporation equation. Using the polarizability, the dipole-dipole binding energy of field-adsorbed noble gases ahs been calculated, and a modified mechanism of field ionization and image interpretation is proposed. A high-voltage field ion microscope has been operated at up to 45 kV, giving an increased field of view.