The kinetics of field adsorption

Abstract

In an applied field of ∼ 1 V/Å or higher, gas atoms and molecules near the electrode surface can be attracted to the surface and be field adsorbed there. Field adsorption can occur at a temperature much higher than that in ordinary physical adsorption. For example, field adsorption of He and Ne on metal surfaces can occur at a temperature above 100 K. The kinetic of field adsorption on spherical, cylindrical and field ion emitter surfaces are discussed. Methods for measuring the field adsorption energy, the gas supply constant, and other physical parameters using the pulsed-laser time-of-flight atom-probe are described. These parameters are essential for describing the kinetics of field adsorption. We consider field adsorption and desorption of both atomic and molecular gases. In molecular gases, field dissociation of field desorbed species can occur. A proper account of this effect has to be included in the data analysis. A case with two adsorption states at different adsorption sites is also considered. Field adsorption must play an important role in the early stages of cloud formation, and in the adsorption-desorption and catalytical reactions on the surface of interstellar particles, etc.