Complex molecular systems studied by modern ab initio multireference methods

电子复杂分子系统，如多核过渡金属簇和多光致变色开关，在化学的许多领域发挥着关键作用。然而，理解和预测它们的性质以及它们的反应性是一个巨大的挑战，也是当前理论化学的前沿之一。近年来，密度矩阵重整化群（DMRG）等替代性多参考方法的发展为充分描述大型电子复杂系统提供了可能性，这些系统很难（如果不是不可能）使用传统方法访问。然而，尽管这些方法具有巨大的潜力，但使用这些方法进行的化学相关研究的数量仍然相当有限，这部分是由于方法问题。在这个Emmy Noether项目中，DMRG的新特性的开发将使两类具有挑战性的化学系统的深入研究成为可能：a)多核铁基交叉偶联催化剂和b)一类新的光开关，施恩-受恩加合物。除了这些前沿应用之外，这项工作将为未来研究其他电子复杂分子系统奠定基础。

Electronically complex molecular systems, such as polynuclear transition metal clusters and multiphotochromic switches, play a key role in many areas of chemistry. Yet understanding and predicting their properties as well as their reactivity is a great challenge and one of the current frontiers of theoretical chemistry. In recent years the development of alternative multireference methods like the density matrix renormalization group (DMRG) has opened up the possibility to adequately describe large and electronically complex systems that are difficult if not impossible to access using conventional methods. However, despite their great potential the number of chemically relevant studies using these methods is still rather limited which is in part due to methodological issues. In this Emmy Noether project the development of novel features for the DMRG will enable the in-depth investigation of two classes of challenging chemical systems: a) polynuclear iron based cross coupling catalysts and b) a novel class of photoswitches, the donor-acceptor Stenhouse adducts. Apart from these cutting edge applications, the work will lay grounds for future investigations of other electronically complex molecular systems.