Exciton coherence lifetimes from electronic structure.
Exciton coherence lifetimes from electronic structure.
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电子结构的激子相干寿命。
DOI：
10.1063/1.3689858
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Alán Aspuru
中科院分区：
文献类型：
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作者：
John A. Parkhill;D. G. Tempel;Alán Aspuru
我们从第一性原理出发，模拟了共价连接的芳香族同源二聚体中电子激发的相干能量转移。我们的结果揭示了通过详细的电子结构计算得出的常用的镀液模型是否能够再现关键的动力学。对于我们所模拟的系统，相干输运的时间尺度是从随时间变化的极化各向异性测量中实验得知的，因此我们可以直接评估目前的技术是否可以预测相干输运的建模。电子自由度与原子核自由度的耦合是从第一原理出发而不是假定的，并且直接再现了荧光各向异性衰变。令人惊讶的是，我们发现尽管含时密度泛函理论的绝对能量通常比单体间的耦合能误差大一个数量级，但这些计算可以半定量地再现这些二聚体的相干输运性质。提出了为产生可预测的和可靠的相干传输模型而必须追求的未来方向。
We model the coherent energy transfer of an electronic excitation within covalently linked aromatic homodimers from first-principles. Our results shed light on whether commonly used models of the bath calculated via detailed electronic structure calculations can reproduce the key dynamics. For the systems we model, the time scales of coherent transport are experimentally known from time-dependent polarization anisotropy measurements, and so we can directly assess whether current techniques are predictive for modeling coherent transport. The coupling of the electronic degrees of freedom to the nuclear degrees of freedom is calculated from first-principles rather than assumed, and the fluorescence anisotropy decay is directly reproduced. Surprisingly, we find that although time-dependent density functional theory absolute energies are routinely in error by orders of magnitude more than the coupling energy between monomers, the coherent transport properties of these dimers can be semi-quantitatively reproduced from these calculations. Future directions which must be pursued to yield predictive and reliable models of coherent transport are suggested.