Electronic Energy Transfer in Condensed Phase Studied by a Polarizable QM/MM Model
Electronic Energy Transfer in Condensed Phase Studied by a Polarizable QM/MM Model
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DOI：
10.1021/ct9001366
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发表时间：
2009-07-01
影响因子：
5.5
通讯作者：
Mennucci, Benedetta
中科院分区：
文献类型：
--
作者：
Curutchet, Caries;Munoz-Losa, Aurora;Mennucci, Benedetta
提出了一种量子力学和分子力学相结合的方法来研究凝聚相中的电子能量转移。该方法引入了基于量子力学的线性响应（LR）计划来描述发色团的电子激发和电子耦合，而环境是通过一个经典的极化力场来描述。显式处理的溶剂电子极化的模型的一个关键方面，因为这允许考虑溶剂屏蔽效应的耦合。该方法进行了测试的模型，在水溶液中的二聚体（PDI）。我们发现一个很好的协议之间的QM/MM方法和“精确”的超分子计算，其中完整的溶质-溶剂系统描述在QM水平，此外，电子耦合的估计被证明是非常敏感的质量的参数来描述溶剂极化。最后，我们比较整体平均QM/MM结果的PCM-LR方法，这是基于连续介质描述的溶剂的预测。我们发现，连续介质和原子溶剂模型的行为相似，在均匀介质，如水。我们的研究结果表明，该方法的潜力，以调查复杂的异质性环境，如蛋白质或纳米结构的主机材料，对EET的作用。
We present a combined quantum mechanics and molecular mechanics (QM/MM) method to study electronic energy transfer (EET) in condensed phases. The method introduces a quantum mechanically based linear response (LR) scheme to describe both chromophore electronic excitations and electronic couplings, while the environment is described through a classical polarizable force field. Explicit treatment of the solvent electronic polarization is a key aspect of the model, as this allows account of solvent screening effects in the coupling. The method is tested on a model perylene diimide (PDI) dimer in water solution. We find an excellent agreement between the QM/MM method and "exact" supermolecule calculations in which the complete solute-solvent system is described at the QM level, In addition, the estimation of the electronic coupling is shown to be very sensitive to the quality of the parameters used to describe solvent polarization. Finally, we compare ensemble-averaged QM/MM results to the predictions of the PCM-LR method, which is based on a continuum dielectric description of the solvent. We find that both continuum and atomistic solvent models behave similarly in homogeneous media such as water. Our findings demonstrate the potential of the method to investigate the role of complex heterogeneous environments, e.g. proteins or nanostructured host materials, on EET.