Anisotropic Dissymmetry Factor, g: Theoretical Investigation on Single Molecule Chiroptical Spectroscopy
Anisotropic Dissymmetry Factor, g: Theoretical Investigation on Single Molecule Chiroptical Spectroscopy
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DOI：
10.1021/jp409559t
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发表时间：
2014-07-10
影响因子：
2.9
通讯作者：
Nakamura, Shinichiro
中科院分区：
文献类型：
--
作者：
Wakabayashi, Masamitsu;Yokojima, Satoshi;Nakamura, Shinichiro
导出了各向异性不对称因子g的计算公式，以求取向固定分子的手性响应。结合零阶和一阶多极展开项，将其应用于桥联的三芳胺螺烯分子，考察了单分子手性光谱的实验结果。用含时密度泛函理论(TDDFT)计算了计算各向异性g值所需的基态和激发态波函数以及一系列跃迁矩。模拟g值的概率直方图显示，即使对于给定的非对映异构体，当电偶极跃迁矩与入射光的传播矢量之间的夹角接近0度或180度时，不对称因子也有正负两个值，并且可以在相当大程度上偏离它们的平均值。
A formula for an anisotropic dissymmetry factor g evaluating the chiroptical response of orientationally fixed molecules is derived. Incorporating zeroth- and first-order multipole expansion terms, it is applied to bridged triarylamine helicene molecules to examine the experimental results of single-molecule chiroptical spectroscopy. The ground- and excited-state wave functions and a series of transition moments required for the evaluation of the anisotropic g value are calculated using time-dependent density functional theory (TDDFT). The probability histograms obtained for simulated g values, uniformly sampled in regard to the direction of light propagation toward the fixed molecule, show that even for a given diastereomer, the dissymmetry factors have positive and negative values and can deviate from their averages to a considerable extent when the angle between the electric dipole transition moment and the propagation vector of the incident light is near 0 or 180 degrees.