发表机构
Universität Rostock; Leibniz-Institut für Katalyse e.V. (LIKAT); Technical University of Munich（罗斯托克大学; 莱布尼兹催化研究所; 慕尼黑工业大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文扩展Frenkel激子模型以纳入交换相互作用，提出非微扰变分表达式，可显著改变耦合符号与大小，从而影响聚集体类型预测，推进多组态体系的光物理建模。
AI 中文摘要
我们提出了Frenkel激子模型的一种扩展，以在分子聚集体中结合单体之间的交换相互作用，并采用多参考电子结构方法。我们的推导结合了Frenkel激子哈密顿量与单电子对交换近似，得到了交换耦合的非微扰变分表达式，该表达式自然排除了任何基组叠加误差。该方法已在OpenMolcas中实现，并可与多参考电子结构技术结合使用。本研究的主要目标是评估交换在具有强多组态特征的系统中的作用。示例表明，在不同近似水平下纳入交换可以显著改变单体间耦合的大小和符号，从而可能将聚集体的预测分类从H型转变为J型。与基于TDDFT的耦合比较凸显了由多参考效应、双激发和Rydberg跃迁引起的显著差异。总体而言，该方法推进了多并苯、类胡萝卜素及其他多组态和Rydberg态至关重要的聚集体中光物理和光化学过程的预测建模。
英文摘要
We present an extension of the Frenkel exciton model to incorporate exchange interactions between monomers in molecular aggregates in conjunction with {a multi-reference electronic structure approach}. Our derivation, {which combines the Frenkel exciton Hamiltonian and the single-electron pair exchange approximation}, yields a non-perturbative, variational expression for the exchange coupling that naturally excludes any basis set superposition error. The method has been implemented in OpenMolcas and enables combination with multi-reference electronic structure techniques. The main objective of the present study is to assess the role of exchange in systems with strong multi-configurational character. Illustrative examples demonstrate how the inclusion of exchange at different levels of approximation can substantially alter the magnitude and sign of intermonomer couplings and thus, for instance, potentially converting the predicted classification of the aggregate from H-type to J-type. Comparison with TDDFT-based couplings highlights significant discrepancies arising from multi-reference effects, double excitations, and Rydberg transitions. Overall, this approach advances the predictive modeling of photophysical and photochemical processes in aggregates of polyacenes, carotenoids, and other systems where multi-configurational and Rydberg states are essential.
