He Nan, Evangelista Francesco A
Department of Chemistry, Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA.
J Chem Phys. 2020 Mar 7;152(9):094107. doi: 10.1063/1.5142481.
Multireference computations of large-scale chemical systems are typically limited by the computational cost of quantum chemistry methods. In this work, we develop a zeroth-order active space embedding theory [ASET(0)], a simple and automatic approach for embedding any multireference dynamical correlation method based on a frozen-orbital treatment of the environment. ASET(0) is combined with the second-order multireference driven similarity renormalization group and tested on several benchmark problems, including the excitation energy of 1-octene and bond-breaking in ethane and pentyldiazene. Finally, we apply ASET(0) to study the singlet-triplet gap of p-benzyne and 9,10-anthracyne diradicals adsorbed on a NaCl surface. Our results show that despite its simplicity, ASET(0) is a powerful and sufficiently accurate embedding scheme applicable when the coupling between the fragment and the environment is in the weak to medium regime.
大规模化学体系的多参考计算通常受到量子化学方法计算成本的限制。在这项工作中，我们开发了一种零阶活性空间嵌入理论[ASET(0)]，这是一种简单且自动的方法，用于基于对环境的冻结轨道处理来嵌入任何多参考动态相关方法。ASET(0)与二阶多参考驱动相似性重整化群相结合，并在几个基准问题上进行了测试，包括1-辛烯的激发能以及乙烷和戊二氮烯中的键断裂。最后，我们应用ASET(0)来研究吸附在NaCl表面的对苯炔和9,10-蒽二自由基的单重态-三重态能隙。我们的结果表明，尽管ASET(0)很简单，但它是一种强大且足够精确的嵌入方案，适用于片段与环境之间的耦合处于弱到中等范围的情况。
