Evaluating excited state atomic polarizabilities of chromophores.
Evaluating excited state atomic polarizabilities of chromophores.
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DOI：
10.1039/c7cp08549d
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发表时间：
2018-03-28
期刊：
影响因子：
--
通讯作者：
Schröder C
中科院分区：
文献类型：
--
作者：
Heid E ;Hunt PA ;Schröder C
用量子力学方法计算了发色团N-甲基-6-羟基喹啉甜菜碱和香豆素153的基态和激发态原子极化率。用含时密度泛函理论（TD-DFT）计算了发色团N-甲基-6-羟基喹啉甜菜碱（MQ）和香豆素153（C153）在溶液中的基态和激发态偶极子及极化率.提出了一种确定原子极化率的方法，将分子偶极分解为原子的电荷转移项和极化率项，并利用电场作用下原子极化率的变化来计算原子的极化率。在激发时，MQ经历了非常特定于位点的极化率变化，而C153显示出显着较小的变化。我们还得出结论，MQ不能充分描述的原子序数和杂化状态的基础上的标准原子极化率。MQ的分子极化率的变化（在激发时）不代表原子极化率的局部位点特异性变化，因此总体分子极化率比不提供激发时局部原子特异性极化率变化的良好近似。溶剂化动力学的计算机模拟需要精确的激发态力场。在这项研究中考虑的发色团经常被用作分子探针。本文的方法和数据可用于构造极化基态和激发态力场。原子和分子的极化率（基态和激发态）已在一系列的泛函和基组进行了评估。不同的机制，包括溶剂化效应进行了研究，使用极化连续模型，明确的溶剂化，并通过采样的集群提取的MD模拟。还考虑了一系列不同的溶剂。
Ground and excited state atomic polarizabilities of the chromophores N-methyl-6-oxyquinolinium betaine and coumarin 153 have been evaluated via quantum mechanics. Ground and excited state dipoles and polarizabilities of the chromophores N-methyl-6-oxyquinolinium betaine (MQ) and coumarin 153 (C153) in solution have been evaluated using time-dependent density functional theory (TD-DFT). A method for determining the atomic polarizabilities has been developed; the molecular dipole has been decomposed into atomic charge transfer and polarizability terms, and variation in the presence of an electric field has been used to evaluate atomic polarizabilities. On excitation, MQ undergoes very site-specific changes in polarizability while C153 shows significantly less variation. We also conclude that MQ cannot be adequately described by standard atomic polarizabilities based on atomic number and hybridization state. Changes in the molecular polarizability of MQ (on excitation) are not representative of the local site-specific changes in atomic polarizability, thus the overall molecular polarizability ratio does not provide a good approximation for local atom-specific polarizability changes on excitation. Accurate excited state force fields are needed for computer simulation of solvation dynamics. The chromophores considered in this study are often used as molecular probes. The methods and data reported here can be used for the construction of polarizable ground and excited state force fields. Atomic and molecular polarizabilities (ground and excited states) have been evaluated over a range of functionals and basis sets. Different mechanisms for including solvation effects have been examined; using a polarizable continuum model, explicit solvation and via sampling of clusters extracted from a MD simulation. A range of different solvents have also been considered.
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影响因子：
3.3
作者：
Beekman, LMP;Frese, RN;vanGrondelle, R
通讯作者：
vanGrondelle, R
影响因子：
3.3
作者：
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影响因子：
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作者：
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影响因子：
4.4
作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
Lagowski, Jolanta B.