Development of new quantum-chemical methods for the description of static correlation effects

静态相关效应在量子化学中非常重要，例如用于描述键断裂或金属系统。拟议的项目涉及发展新的量子化学方法来描述这些效应。计划将波函数的广义耦合簇展开与底层单电子轨道的同时优化结合起来。随着大尺度应用范围的扩大，动态相关效应的微扰展开式有待发展。在将上述想法作为有效的计算机代码实现之后，这些发展的好处将通过以下系统的示例应用来证明：(a)反应机制（羧基自由基的衰变），(b)过渡金属化学（与过渡金属原子的基本反应）和(c)分子导体（硫氮低聚物）。

Static correlation effects are of great importance in quantum chemistry, e.g. for the description of bond breaking or metallic systems. The proposed project deals with the development of new quantum chemical methods to describe these effects. It is planned to combine a generalized coupled-cluster expansion of the wavefunction with a simultaneous optimization of the underlying one-electron orbitals. With the scope of large scale applications, perturbation expansions for dynamic correlation effects are to be developed. After implementation of the above ideas as an efficient computer code, the benefit of these developments shall be demonstrated with sample applications on the following systems: (a) Reaction mechanisms (decay of carboxyl radicals), (b) transition metal chemistry (elementary reactions with transition metal atoms) and (c) molecular conductors (sulfur-nitride-oligomers).