LENS, Polo Scientifico e Tecnologico, Università di Firenze, via N. Carrara 1, 50019 Sesto Fiorentino, Italy.
Phys Chem Chem Phys. 2010 Nov 7;12(41):13547-54. doi: 10.1039/c002992k. Epub 2010 Sep 27.
Integrated experimental and computational results help to clarify the nature of the intermolecular interactions in a simple, isolated π-stacked dimer prepared in a molecular beam. The properties of bimolecular anisole complexes are examined and discussed in terms of the local/supramolecular nature of the electronic wavefunctions. Experimental resonance-enhanced multi-photon ionization spectra of clusters with different isotopic compositions confirmed the fundamentally localized nature of the S(1)←S(0) electronic transition. A detail analysis of the experimental results however shows the existence of non-negligible excitonic coupling for the excited-state wavefunctions leading to the doubling of the single-molecule vibronic levels in the S(1) state, with a splitting of about 30 cm(-1). Theoretical simulation of the vibrationally resolved electronic spectra and computations of the excitonic coupling convincingly support the experimental findings. The overall combined experimental/theoretical study allows a detailed description of the stacking interaction in the anisole dimer.
综合实验和计算结果有助于阐明在分子束中制备的简单孤立π堆积二聚体中分子间相互作用的本质。根据电子波函数的局部/超分子性质，研究并讨论了双分子苯甲醚络合物的性质。不同同位素组成的团簇的实验共振增强多光子电离光谱证实了 S(1)←S(0)电子跃迁的基本局域性质。然而，对实验结果的详细分析表明，激发态波函数中存在不可忽略的激子耦合，导致 S(1)态中单分子振动能级的倍增，分裂约 30 cm(-1)。振动分辨电子光谱的理论模拟和激子耦合的计算令人信服地支持了实验结果。综合实验/理论研究允许对苯甲醚二聚体中的堆积相互作用进行详细描述。
