A density-functional study of the effects of an external electric field on admolecule-surface systems

Abstract

The influence of an external electric field of a magnitude typical of those in STM current-induced excitation experiments on the admolecule-surface and intramolecular bonds of OH, BeH and NO adsorbed on Si(111) and BH on C(111) is investigated using ab initio density functional cluster techniques. These systems represent four distinct adsorbate-surface electronic polarization configurations. The bonding parameters are calculated as a function of the strength and direction of the electric field. The field-induced changes in the characteristics of both the admolecule-surface and the intramolecular bonds show strong dependence on their polarization configuration. © 1998 Elsevier Science B.V. All rights reserved.