Quantum Dynamics and Control of Surface Ultra-fast Processes

表面超快过程的量子动力学和控制

基本信息

批准号：
16072206
负责人：
YAMASHITA Koichi
金额：
$ 16.77万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

Photochemistry on Metal Surfaces: To understand photochemical reactions on surfaces, electronic excitation mechanisms should be specified, and it is well known that the substrate-mediated (indirect) excitation occurs in the majority of reactions on metal surfaces. We have developed a new theoretical method to calculate photon energy dependence of reaction probability triggered by substrate-mediated excitation using Nonequilibrium Green's function (NEGF) theory. We have performed DFT calculations to obtain the dimer adsorption structure and calculated the probability of photodesorption based on our NEGF theory. We have found that while the photoactive species is the NO dimer, a suitable resonant orbital is only one, and this single resonance is enough to reproduce the experimental data.A NEGF approach to interfacial electronic quantum transport: To model electron transport through a molecular junction, we propose an efficient method using an ab initio self-consistent NEGF combined with density functional theory. We have adopted a model close to the extended molecule approach, due to its flexibility, but have improved on the problems relating to molecule-surface couplings and the long-range potential via a systematic procedure for the same ab initio level as that of the Green's function. The resulting algorithm involves three main steps: (i) construction of the embedding potential; (ii) perturbation expansion of the Green's function in the molecular orbital basis; and (iii) truncation of the molecular orbital space by separating it into inactive, active, and virtual spaces. The algorithm is suitable for application to large molecular systems.

金属表面的光化学：要了解表面上的光化学反应，应明确电子激发机制，众所周知，金属表面上的大多数反应都发生底物介导（间接）激发。我们开发了一种新的理论方法，使用非平衡格林函数（NEGF）理论来计算由底物介导的激发触发的反应概率的光子能量依赖性。我们进行了DFT计算以获得二聚体吸附结构，并根据我们的NEGF理论计算了光解吸的概率。我们发现，虽然光活性物质是 NO 二聚体，但合适的共振轨道只有一个，并且这个单一共振足以重现实验数据。界面电子量子传输的 NEGF 方法：模拟通过分子结的电子传输，我们提出了一种使用从头算自洽 NEGF 与密度泛函理论相结合的有效方法。由于其灵活性，我们采用了接近扩展分子方法的模型，但通过与格林模型相同的从头计算水平的系统程序，改进了与分子表面耦合和远程势相关的问题功能。由此产生的算法涉及三个主要步骤：（i）构建嵌入势； (ii) 分子轨道基础上格林函数的微扰展开； (iii) 通过将分子轨道空间分为非活性空间、活性空间和虚空间来截断分子轨道空间。该算法适合应用于大分子系统。