J. Phys. Colloques
Volume 49, Numéro C6, Novembre 198835th International Field Emission Symposium / 35éme Symposium International d'Emission de Champ
|Page(s)||C6-3 - C6-6|
J. Phys. Colloques 49 (1988) C6-3-C6-6
THEORY OF FIELD ADSORPTIONH.J. KREUZER
Department of physics, Dalhousie University, Halifax, N.S., B3H 3J5, Canada
A first principles theory is formulated to calculate the dispersion (van der Waals) and polarization (induced dipole-dipole) interactions between a solid and an atom in a strong electric field. It is shown that these forces are not strong enough to bind rare gases on field ion tips. We then review a microscopic theory of field adsorption in which the electronic properties of the metal-adsorbate system are calculated within a tight binding cluster approach based on the ASEDMO method with local electric fields taken from self-consistent hellium calculations. Comparison with experiment for helium field adsorption on tungsten is excellent for activation energies, bonding distances and vibrational frequencies. Reference will also be made to the field-induced chemistry of NO on a platinum tip.