Does Förster theory predict the rate of electronic energy transfer for a model dyad at low temperature?
Does Förster theory predict the rate of electronic energy transfer for a model dyad at low temperature?
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福斯特理论是否可以预测低温下双体模型的电子能量转移速率？
DOI：
10.1021/jp7106507
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
D. Beljonne
中科院分区：
文献类型：
--
作者：
C. Curutchet;B. Mennucci;G. Scholes;D. Beljonne
使用福斯特模型来预测在低温下嵌入 PMMA 基质中的模型供体-受体二元体（三联苯桥联苝二酰亚胺 (PDI)-三联苯二酰亚胺 (TDI) 二元体分子）中的共振电子能量转移 (RET) 动力学，并进行了实验测试。 RET 福斯特速率中涉及的相关成分，即电子耦合、光谱重叠和屏蔽效应，均以定量方式加以说明。电子耦合是通过时间相关的密度泛函理论计算获得的，PMMA 环境的影响包括在 IEFPCM 模型中对跃迁密度及其相互作用的影响。我们发现三联苯桥的存在导致桥上 PDI 和 TDI 跃迁密度的轻微离域，这是由于耦合增加了 56%，并且偶极-偶极近似的破坏。光谱重叠是根据均匀加宽的供体发射和受体吸收线形状的详细模拟来确定的，该形状是通过拟合在 1.2 K 下测量的单分子光谱确定的。然后通过假设供体和受体的不相关的不均匀线加宽来估计整个系综中光谱重叠的相应分布。结合计算出的电子耦合和从能量无序的蒙特卡罗实现中采样的光谱重叠，我们获得了平均 RET 时间（大约 8 ps）和与实验合理一致的分布。
The use of the Förster model to predict the dynamics of resonant electronic energy transfer (RET) in a model donor-acceptor dyad (a terphenyl-bridged perylene diimide (PDI)-terrylene diimide (TDI) dyad molecule) embedded at low temperature in a PMMA matrix is tested against experiment. The relevant ingredients involved in the Förster rate for RET, namely electronic coupling, spectral overlap, and screening effects, are accounted for in a quantitative manner. Electronic couplings are obtained from time-dependent density functional theory calculations, and the effect of the PMMA environment is included both on the transition densities and on their interaction through the IEFPCM model. We find that the presence of the terphenyl bridge induces a slight delocalization of the PDI and TDI transition densities over the bridge originating in a 56% increase in the coupling and in the breakdown of the dipole-dipole approximation. The spectral overlap is determined on the basis of a detailed simulation of the homogeneously broadened donor emission and acceptor absorption line shapes determined by fitting the single molecule spectra measured at 1.2 K. The corresponding distribution of spectral overlap throughout the ensemble is then estimated by assuming an uncorrelated inhomogeneous line broadening for the donor and acceptor. Combining the calculated electronic couplings and spectral overlaps sampled from Monte Carlo realizations of the energetic disorder, we obtain a mean RET time (approximately 8 ps) and a distribution in reasonable agreement with experiment.