Microcosmic Kinetics Studies Of The Adsorption Of N And H Atoms On Transition Metal Surface

With the rapid development of chemical industry, solid catalysts and the promoted reactions have received considerable attention during the past decades. And the surface adsorption as the key of the catalysis between different phases has taken on more and more expansive prospect. The kinetic behavior of adsorption, vibration and diffusion on transition metals W and Pt surfaces of H, N atoms was studied by 5-MP method. Meanwhile, the 2H-W(100) surface system was studied by the extended LEPS method for investigating the subsurface adsorption state effect on the surface adsorption state. The calculation results reproduced the obtained experimental data and predict some important information that has not been observed. The main contents of this work are as follows:1) The effect mechanism between atoms and transition metal surfaces was studied by 5-MP method. Caculation results reproduced the dynamic characteristics of atom adsorption on low index transition metals surface, such as the adsorption sites, the adsorption geometry, the binding energy and the eigenvibration etc. For the H-Pt(111) system, this work carried out thorough analysis on the assignment about loss peak observed in the experiment, and put forward credible estimate for loss peak by theoretical analysis. The 68meV and 112meV from experiment are attributed to the parallel and perpendicular vibration frequency for threefold adsorption state of hydrogen atom, respectively; the 153meV is attributed to the perpendicular vibration frequency for subsurface adsorption state of hydrogen atom.2) The interaction of 2H-W(100) surface system was studied using the extended LEPS constructed by 5-MP method. If two adsorption state distances are farther, the interaction between adsorption states becomes very weak, the character change of two adsorption state becomes smaller. This work studies that the interaction between adjacent adsorption sites of the comparatively big character changes of critical point, especially for effect of the subsurface adsorption state on the adjacent surface adsorption state. Results are obtained: The preferential adsorption of second-layer subsurface bridge adsorption site B_s affects the critical point character of adjacent surface fivefold hollow H(B_s) and bridge B(B_s) adsorption sites to some extent. The perpendicular vibration frequency of H(B_s) site becomes 153meV from 171meV; the perpendicular vibration...