Department of Chemistry, The Norwegian University of Science and Technology, Trondheim, Norway.
Scuola Normale Superiore, Pisa, Italy.
J Comput Chem. 2021 Jul 30;42(20):1419-1429. doi: 10.1002/jcc.26553. Epub 2021 May 11.
In this article, we use two extensively studied systems, a retinal model system and azobenzene, to explore the use of coupled cluster models for describing ground and singlet excited state potential energy surfaces of photoswitchable systems. While not being suitable for describing nuclear dynamics of photoisomerization, coupled cluster models have useful attributes, such as the inclusion of dynamical correlation, their black box nature, and the systematic improvement offered by truncation level. Results for the studied systems show that when triple excitations (here through the CC3 model) are included, ground and excited state potential energy surfaces for isomerization paths may reliably be generated, also for states of doubly excited character. For ground state equilibrium cis- and trans-azobenzene, the molecular geometry and basis set is seen to significantly impact the vertical excitation energies for the two lowest excited states. Efficient implementations of coupled cluster models can therefore constitute valuable tools for investigating photoswitchable systems and can be used for preliminary black box studies to gather information before more complicated excited state dynamics approaches are pursued.
在本文中，我们使用两个经过广泛研究的系统，视网膜模型系统和偶氮苯，来探索耦合簇模型在描述光致开关系统的基态和单重激发态势能表面中的应用。虽然耦合簇模型不适合描述光异构化的核动力学，但它们具有有用的属性，例如包含动力学相关、黑盒性质以及截断水平提供的系统改进。对于所研究的系统，结果表明，当包含三重激发（这里通过 CC3 模型）时，可以可靠地生成异构化路径的基态和激发态势能表面，也可以生成具有双重激发特征的状态。对于基态平衡的顺式和反式偶氮苯，分子几何形状和基组被认为对两个最低激发态的垂直激发能有显著影响。因此，耦合簇模型的高效实现可以构成研究光致开关系统的有价值的工具，并且可以用于初步的黑盒研究，在追求更复杂的激发态动力学方法之前收集信息。
