年来，有机分子在金属基底上的自组装为制备较大的纳米结构、微型器件等提供了一种新颖有效的“自下而上”的方式，成为了当前的研究热点。金属基底与有机分子形成的界面在异质催化反应，电化学传感器，非线性光学材料等许多重要的领域中也有着广泛的应用。通常，分子在金属上有两种吸附形态:化学吸附和物理吸附。不同的吸附状态与衬底会产生不同的交互作用，进而会导致有机杂化界面材料在电学和光学性质上的不同。

研究表明，通过官能团修饰如卤化、元素取代等手段可以实现分子在金属表面吸附构型的调控。尽管如此，人们在原子、分子尺度上对单分子金属基底的相互作用的理论研究仍然处在初始阶段，这对分子在金属基底吸附构型的调控造成了很大的困难。基于第一性原理计算，采用先进的DFT+vdWsurf方法，对于不同的有机分子的吸附结构和吸附能进行系统的研究，将对有机分子的调控有着重要的指导意义。

关键词 化学吸附 物理吸附 官能团修饰 第一性原理

毕业设计说明书外文摘要

Title Modification of Adsorption Structure and Stability of Organic Molecules on the Metal surfaces

Abstract：Recently, the self-assembly of organic molecules on metal substrates has provided a novel and effective "bottom-up" approach to the preparation of larger nanostructures and micro-devices, which has become a hot topic. The interface between the metal substrate and the organic molecules also has a wide range of applications in heterogeneous catalytic reactions, electrochemical sensors, nonlinear optical materials, and lots of other important fields. In general, there are two adsorption states of molecules on the metal surface: chemisorption and physisorption. At different adsorption states, the molecules would present different interactions with the substrate, which leads to different electronic and optical properties.

It is shown that the tuning of the adsorption structure of the molecules on the metal surface can be realized by modifying the functional groups such as halogenation and element substitution. Nevertheless, the theoretical study of the interaction of molecules at the atomic and molecular scales on the monomolecular metal substrate is still at the initial stage, which makes it difficult to tune the adsorption structure of the metal substrate. Based on the first-principles calculation, the state of the art DFT + vdWsurf method is used to study the adsorption structure and adsorption energy of different organic molecules, which will be of great significance to the regulation of organic molecules.

Keywords Chemisorption Physisorption Modification of functional groups The first principle

目 次

1绪论 1

1.1引言 1

1.2分子器件 1

1.2.1分子器件的发展 1

1.2.2分子开关 2

1.3课题工作 4

2密度泛函理论 5

2.1 Hohenberg‐Kohn定理：多体理论 6

2.2 Kohn‐Sham方程：有效单体理论 7

2.3交换关联泛函 7

2.3.1局域密度近似（LDA） 8

2.3.2广义梯度近似（GGA）