Development and Application of Quantum-Chemical Density-Matrix Renormalization Group Methods

密度矩阵重整化群(DMRG)是固体物理学中用来计算多粒子相互作用体系中电子关联效应的一个新概念。它最近已经在一个适用于分子中多粒子相互作用和电子关联的从头计算的版本中实现。目前的项目旨在将这种量子化学版本的DMRG发展成为分子电子结构计算中具有竞争力的计算工具。我们建议使用DMRG技术来处理大的电子活性空间(对于过渡金属和类光化化合物来说是典型的)，这是到目前为止用传统的活性空间方法无法处理的。该项目包括新技术的方法开发和数值案例研究，这对于评估DMRG有效处理分子中遇到的各种类型的电子相关效应的能力非常重要。

The density-matrix renormalization group (DMRG) is a novel concept developed in solid-state physics to calculate electron correlation effects in interacting many-particle systems. It has recently been implemented in a version suitable for an ab initio calculation of many-particle interactions and electron correlation in molecules. The current project aims at developing this quantum-chemical version of DMRG to a competitive calculational tool in molecular electronic structure calculations. We propose to use DMRG techniques to treat large active spaces of electrons (typical for transition-metal and actinoid compounds) which could not be handled to date using conventional active-space methods. The project comprises method development as well as numerical case studies with the new technique which are important to assess the power of DMRG to efficiently treat the various types of electron correlation effects encountered in molecules.