The development of quantitative molecular orbital theory for mesoscopic systems and its application to the initial chemical process of vision

从化学观点看，介观体系包括许多重要的体系，如溶质-溶剂体系、分子-表面体系、扩展体系和团簇。本研究的目的是发展一个定量的分子轨道理论和一个程序包的介观系统，并将它们应用于视觉的初始化学过程。重点特别放在以下主题上：1。发展多组态SCF和Kohn-Shem DFT方法用于大尺度系统，2。发展大尺度系统的电子相关方法，特别是基于多参考的微扰理论MC-QDPT，和3。大尺度体系的电子结构和化学反应研究.在从头算分子轨道理论中，确定分子轨道的有效方案至关重要。首先，我们已经开发了一个高效的分子积分算法和程序，这是必不可少的初始步骤的MO确定，然后开发QCAS-SCF，弦积空间SCF，和一般MC-SCF方法。这些MC-SCF方法只处理化学上重要的电子构型，因此比CAS-SCF方法、常规MC-SCF方法更有效。我们还提出了大尺度系统的Kohn-Sham DFT方法，使用非正交局域MO.为了考虑电子相关效应，我们发展了QCAS-QDPT、GMC-QDPT、MROPT-PT和MR-Brillouin-Wigner PT。这些PT是基于上一期发展的紧致波函数，因此它们适用于大尺度系统.利用这些MC-SCF和微扰方法，我们已经在分子包括大尺度体系中取得了以下应用：多电荷阴离子的设计，CT化合物的中性-离子跃迁的分析，五元环化合物的高激发态的识别，以及长多烯的电子结构。

The mesoscopic system includes many important systems, from chemical point of view, as solute-solvent systems, molecular-surface systems, extended systems, and cluster. The aim of the present research was to develop a quantitative molecular orbital theory and a program package for the mesoscopic system and to apply them to the initial chemical process of vision. The focus was especially on the following topics : 1. Development of multiconfiguration SCF and Kohn-Shem DFT methods for large-scale systems, 2. Development of electron correlation methods for large-scale systems, in particular a multireference based perturbation theory MC-QDPT, and 3. Studies on the electronic structure and chemical reaction of large-scale systems.1. In ab initio MO theory, an efficient scheme for determining MOs is crucial. First we have developed a highly efficient molecular integral algorithm and program, which is essential as the initial step of MO determination, and then developed QCAS-SCF, string-product space SCF, and general MC-SCF methods. These MC-SCF methods treat only chemically important electronic configuration and thus more effective than the CAS-SCF method, the conventional MC-SCF method. We have also presented Kohn-Sham DFT method for large-scale systems, using non-orthogonal localized MOs.2. For the inclusion of electron correlation effect, we developed QCAS-QDPT, GMC-QDPT, MROPT-PT, and MR-Brillouin-Wigner PT. These PTs are based on the compact wave functions developed in the previous term, and therefore they are applicable to large-scale systems.3. With these MC-SCF and perturbation methods, we have made the following applications to molecules including large-scale systems : Design of multiply charged anions, analysis of the neutral-ionic transition of CT compounds, identification of highly excited states of five-membered ring compounds, and electronic structure of long polyenes.