Angelico Sara, Kjønstad Eirik F, Koch Henrik
Department of Chemistry, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway.
J Phys Chem Lett. 2025 Jan 16;16(2):561-567. doi: 10.1021/acs.jpclett.4c03274. Epub 2025 Jan 7.
Minimum energy conical intersections can be used to rationalize photochemical processes. In this Letter, we examine an algorithm to locate these structures that does not require the evaluation of nonadiabatic coupling vectors, showing that it minimizes the energy on hypersurfaces that envelop the intersection seam. By constraining the states to be separated by a small non-zero energy difference, the algorithm ensures that numerical artifacts and convergence problems of coupled cluster theory at conical intersections are not encountered during the optimization. In this way, we demonstrate for various systems that geometries at minimum energy conical intersections with the ground state are well described by the coupled cluster singles and doubles model, suggesting that coupled cluster theory may, in some cases, provide a good description of relaxation to the ground state in nonadiabatic dynamics simulations.
最小能量锥形交叉点可用于合理解释光化学过程。在本信函中，我们研究了一种定位这些结构的算法，该算法无需评估非绝热耦合矢量，结果表明它能使围绕交叉点缝的超曲面上的能量最小化。通过将态约束为被一个小的非零能量差隔开，该算法确保在优化过程中不会遇到锥形交叉点处耦合簇理论的数值伪影和收敛问题。通过这种方式，我们针对各种系统证明，与基态的最小能量锥形交叉点处的几何结构可以通过耦合簇单双激发模型得到很好的描述，这表明在某些情况下，耦合簇理论可能为非绝热动力学模拟中向基态的弛豫提供良好的描述。
