Atoms, Molecules And Metal Surface Interaction Dynamics Study

The interaction between atoms, molecules and metallic surfaces is an important research topic in the field of heterogeneous catalysis, gas erosion and crystal growth. Theoretical study on a molecular level can not only help understand the interaction mechanism between the absorbent and metallic surfaces, but also acquire the kinetic information of adsorption and surface diffusion. Some representative atoms and molecules are selected to study the kinetic behavior of adsorption and dissociation on the flat and defective surfaces by employing five-parameter Morse potential and improved extended LEPS potential in this dissertation. This method has three merits: (1) The five parameters are irrespective of surface structure. They can be employed in the flat and defective surfaces at the same time. (2) When dispose the interaction between molecule and surface, we replace the atom-surface potential of extended LEPS potential with five-parameter Morse potential. When we synchronously adjust three Sato parameters on three low index surfaces, the interaction potential between molecular and surface is surely independent of the metallic surface structure. It can also be employed to the defective surfaces. (3) This method employs sufficiently large Cluster to simulate ideal flat plane and defective terrace. Simultaneity, we put forward a method---multi-body Morse potential梩o construct the interaction potential of H20. Kinetic calculation was simulated on the potential energy surface by QCT method. The whole paper is divided into four chapters. 73 Chapter 1, Preface, it describes the meaning of study, the experimental and theoretical methods in studying the adsorption. Morse potential method and improved extended LEPS potential method were introduced in detail. Chapter 2, 5-parameter Morse potential method is employed to study the interactional systems of 0-Pd and N-Ni about the characteristic of adsorptive critical point and the structure of diffused potential energy surface. Moreover, this method was also employed to study the interactional systems of 0-Pd (115) and N-Ni (510) ,to discussed the effect of step about the adsorptive diffusion of atom. Our theoretical results are in agreement with experimental results. This indicates that our method is credible and usable. Chapter 3, Improved extended LEPS potential method is employed to study the interactional systems of NO-Ni, OH-Ni and 02-Pd about the characteristic of adsorptive critical point and dissociative diffusion potential energy surface. Moreover, this method was also employed to study the effect of Ni (510) step terrace about the dissociative adsorption of NO. The role of the step is that (1) at the terraces under the step, the direct dissociative paths are increased and the translational activation potential barriers are decreased obviously. (2) at the terraces above the step and near step edge, the precursor adsorptive energies are decreased, the desorption paths are increased. Thus the step are the active regions for the dissociation and association of molecule. These results simultaneous indicate that the dissociation of molecular requires at least two adjacent empty sites, which show why dissociation is inhibited at high coverage. Our theoretical results are in agreement with experimental...