Can Excited State Electronic Coherence Be Tuned via Molecular Structural Modification? A First-Principles Quantum Electronic Dynamics Study of Pyrazolate-Bridged Pt(II) Dimers.
Can Excited State Electronic Coherence Be Tuned via Molecular Structural Modification? A First-Principles Quantum Electronic Dynamics Study of Pyrazolate-Bridged Pt(II) Dimers.
复制标题
可以通过分子结构修饰来调节激发态电子相干性吗？
DOI：
10.1021/acs.jpca.6b12099
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Xiaosong Li
中科院分区：
文献类型：
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作者：
D. Lingerfelt;Patrick J. Lestrange;Joseph J Radler;Samantha E Brown;Pyosang Kim;F. Castellano;Lin X. Chen;Xiaosong Li
表现出长寿命电子相干的材料和分子系统可以促进相干传输，打开了超越传统方法的高效电荷和能量传输的大门。最近，在双核铂配合物的飞秒泵浦-探测光谱实验中，发现了可能的相干、重复的电子运动的特征，其中观察到了瞬时吸收信号的各向异性中持续的周期性拍动。在这项研究中，我们研究了一系列双核铂络合物的激子动力学，这些激子动力学是怀疑电子相干的基础，这些双核铂络合物表现出一定的铂间距。结果表明，只有当竞争性电子耦合达到平衡时，才能产生长寿命的相干。在较长的铂-铂距离下，双核系统两半之间的电子耦合减弱，有利于激子在短时间尺度上的局域化和复合。对于较短的铂-铂距离，相干叠加态之间的电子耦合比与其他激子态的耦合更强，从而导致长寿命相干。
Materials and molecular systems exhibiting long-lived electronic coherence can facilitate coherent transport, opening the door to efficient charge and energy transport beyond traditional methods. Recently, signatures of a possible coherent, recurrent electronic motion were identified in femtosecond pump-probe spectroscopy experiments on a binuclear platinum complex, where a persistent periodic beating in the transient absorption signal's anisotropy was observed. In this study, we investigate the excitonic dynamics that underlie the suspected electronic coherence for a series of binuclear platinum complexes exhibiting a range of interplatinum distances. Results suggest that the long-lived coherence can only result when competitive electronic couplings are in balance. At longer Pt-Pt distances, the electronic couplings between the two halves of the binuclear system weaken, and exciton localization and recombination is favored on short time scales. For short Pt-Pt distances, electronic couplings between the states in the coherent superposition are stronger than the coupling with other excitonic states, leading to long-lived coherence.