Field adsorption, desorption and evaporation.
Date
1992
Authors
Wang, Richard Liang-Chen.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
Using the density-functional theory with the local density approximation for the field adsorption of transition metal atoms, titanium and niobium, we obtain the electric field distribution and, especially, the field enhancement above an adsorbed metal atom. From detailed analyses of electron distributions of the rare-gas atoms, helium and neon, field-adsorbed on metals, we demonstrate that the increase in binding energies to several hundred meV with increasing field strengths can be attributed to a transition from physisorption in weak fields to field-induced chemisorption in strong fields.
We construct diabatic states from adiabatic ones by using a unitary transformation for the thermal field-desorption of helium from tungsten and developing a perturbational method for the field-evaporation of tungsten, respectively. The diabatic states form the basis to compute the temperature-dependent ionization probabilities for singly-charged ions. Employing a master equation, we calculate the energy-dependent ion yield as a function of field strength and temperature, and extract the field dependence of the activation barrier and prefactor.
Thesis (Ph.D.)--Dalhousie University (Canada), 1992.
We construct diabatic states from adiabatic ones by using a unitary transformation for the thermal field-desorption of helium from tungsten and developing a perturbational method for the field-evaporation of tungsten, respectively. The diabatic states form the basis to compute the temperature-dependent ionization probabilities for singly-charged ions. Employing a master equation, we calculate the energy-dependent ion yield as a function of field strength and temperature, and extract the field dependence of the activation barrier and prefactor.
Thesis (Ph.D.)--Dalhousie University (Canada), 1992.
Keywords
Chemistry, Physical.