Combined Electronic Structure Theory of Relativity, quasi-degeneracy, and Electron Correlation Oriented Towards Electric and Magnetic phenomena in molecules

在这个研究项目中，我们发展了适用于准简并体系、相对论和动态电子相关问题的电子结构理论和方法，并开展了一些电磁物质中分子性质的基础性研究。他基于直接微扰理论研究了电子的短程行为，并首次将动量平衡的相对论双基应用于多电子系统。此外，Ten-no还提出了一种新的量子蒙特卡罗(QMC)方法来处理强关联系统的准简并和激发态。他发展了模型空间QMC(MSQMC)方法来随机确定有效的哈密顿量。MSQMC超越了标准从头算方法的局限性，Nakano发展了相对论占领受限多活动空间多…更组态自洽场方法(ORMAS-SCF)及其二阶微扰理论。他将它们应用于稀土和过渡金属化合物的激发态，作为磁性或电致发光材料的模型络合物。为了计算包括高度相对论效应在内的各种方法，他还对负能自旋效应进行了系统的研究。他将多电子无限阶Douglas-Kroll-Hess(IODKH)方法与精确计算激发态电子结构的SAC-CI方法相结合。柳井正发展了从头算密度矩阵重整化群(DMRG)方法，实现了含重元素分子体系的高精度电子结构计算。作为实际应用，将DMRG方法应用于多核过渡金属络合物的电子结构研究。我们的计算提供了对金属位置的氧化态的详细的理论分析，在这些位置上解释实验观察有相当大的困难。此外，还发展了将通常在重金属体系中产生的自旋-轨道效应纳入DMRG波函数的方法。较少

In this research project, we developed the electronic structure theories and methods which can applied to quasi-degenerate systems, relativistic and dynamic electron-correlation problems, and executed some fundamental researches of molecularproperties in electric and magnetic substances.Ten-no developed a four-component relativistic MP2-F12 method to treat molecules with heavy elements accurately. He investigated the short-range behavior of electrons based on the direct perturbation theory and applied a kinetically-balanced relativistic geminal basis to multi-electronic systems for the first time. Furthermore, Ten-no proposed a new quantum Monte Carlo (QMC) method to treat quasi-degenerate and excited sates of strongly correlated systems. He developed the model space QMC (MSQMC) method to determine an effective Hamiltonian stochastically. MSQMC transcends the limitation of the standard ab initio methods.Nakano developed the relativistic occupation restricted multiple active space multi … More configuratoinal self-consistent field method (ORMAS-SCF) method and second-order perturbation theory based on it. He applied them to the excited states of rear-earth and transition metal compounds as model complexes of magnetic or electroluminescentmaterials. He also made a systematic investigation on the effect of the negative energy spinors in order to estimate the methods including the highly relativistic effects.Hada combined the many-electron Infinite-order Douglas-Kroll-Hess ()IODKH) method with the SAC-CI method which is an accurate electronic structure method for excited states. He applied this method to molecular magnetic properties of heavy-metal complexes.Yanai developed ab initio density matrix renormalization group (DMRG) method to achieve high accuracy electronic structure calculations for molecular systems containing heavy elements. As its practical application, the DMRG method was applied for the study of the electronic structures of multi-nuclear transition metal complexes. Our calculations provided detailed theoretical analysis of oxidation states of metal sites where there are considerable difficulties in interpreting experimental observations. In addition, the method to incorporate the spin-orbit effects, typically arising in heavy metal systems, into the DMRG wave function was developed. Less