Theory of Negative Ion Formation by Adsorbed Molecules

9319436 Rous一个全面的理论描述共振电子散射的分子吸附在固体表面将被开发和应用于了解表面负离子形成的基本物理。计算方法将基于层- kohn - korringa - rostoker理论，该理论将充分考虑基片和表面势垒对捕获电子的多重散射。因此，基底的未占据电子结构对分子共振的影响将被模拟。共振寿命和能量对分子吸附高度（表面以上）、吸附位置和分子取向的依赖将被探索，以阐明分子的吸附几何形状和瞬态（共振）状态行为之间的联系。在各种电子和光子刺激的表面动力学过程中，主要定位于被吸附分子上的短寿命的“共振”电子态是已知重要的。所提出的工作涉及到通过计算密集的方法来表征这些状态的能量和它们的寿命。这项工作将集中在附近表面的存在如何影响自由空间分子的共振状态，以及这些状态如何作为分子相对于表面的位置和方向的函数而变化。＊＊＊

9319436 Rous A comprehensive theoretical description of resonance electron scattering by molecules adsorbed on solid surfaces will be developed and applied to understand the fundamental physics of negative ion formation at surfaces. The computational methodology will be based upon the layer-Kohn-Korringa-Rostoker theory which will fully incorporate the multiple scattering of the trapped electron by the substrate and surface barrier. Thus the influence of the unoccupied electronic structure of the substrate on the molecular resonance will be modelled. The dependence of resonance lifetime and energy upon the molecular adsorption height (above the surface), adsorption site and molecular orientation will be explored in order to elucidate the link between the adsorption geometry of a molecule and the behavior of the transient (resonance) state. %%% In a variety of electron and photon stimulated surface dynamical processes, short lived "resonance" electronic states localized mainly upon the adsorbed molecule are known to be important. The proposed work concerns itself with characterizing both the energy of these states and their lifetime via computationally intensive methodologies. The work will concentrate on how the presence of the nearby surface affects the resonance states of the free-space molecule and, further, how these states vary as a function of the location and orientation of the molecule relative to the surface. ***