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Nonstationary Theory of Excited State Charge Transfer Symmetry Breaking Driven by Polar Solvent
The Journal of Physical Chemistry B ( IF 2.8 ) Pub Date : 2020-11-16 , DOI: 10.1021/acs.jpcb.0c07612
Alexey E. Nazarov 1 , Anatoly I. Ivanov 1
Affiliation  

A consistent theory of electron transfer symmetry breaking (SB) dynamics in excited quadrupolar molecules in polar solvents is developed. The interaction of the electronic subsystem of the molecule with intramolecular degrees of freedom and solvent polarization is taken into account and is divided into interaction with inertial and inertialess degrees of freedom. A strong influence of the inertialess polarization of the solvent on the extent of symmetry breaking is revealed. The theory is nonlinear due to the equilibration of inertialess degrees of freedom to the solute electronic state. The interaction of a molecule with the inertial solvent polarization is described in terms of a single variable—the reaction coordinate, for which a rigorous definition is given. The free energy of the system is derived, and the motion of the system along the reaction coordinate is modeled by the Smoluchowski equation. The theory is adapted to describe the dynamics of SB in real solvents characterized by several relaxation time scales. Conditions for the applicability of a much simpler stationary SB model are formulated. The role of thermal fluctuations in the solvent polarization is clarified. Instead of the magnitude of the dissymmetry parameter, a distribution function of molecules over this parameter is introduced. An analysis of the Franck–Condon state created by a short pump pulse shows that it has distinct features of a state with broken symmetry for a wide range of parameters. Thermal fluctuations of the solvent polarization are shown to crucially affect SB.

中文翻译:

极性溶剂驱动的激发态电荷转移对称性打破的非平稳理论

建立了在极性溶剂中激发的四极分子中电子转移对称性破坏(SB)动力学的一致理论。考虑了分子电子子系统与分子内自由度和溶剂极化的相互作用,并分为与惯性和无惯性自由度的相互作用。揭示了溶剂的无惯性极化对对称破坏程度的强烈影响。由于无惯性自由度与溶质电子态的平衡,因此该理论是非线性的。分子与惯性溶剂极化的相互作用是用一个变量(反应坐标)描述的,对此给出了严格的定义。系统的自由能被导出,系统沿着反应坐标的运动由Smoluchowski方程建模。该理论适用于描述以几种弛豫时间尺度为特征的实际溶剂中SB的动力学。制定了适用于简单得多的固定式SB模型的条件。阐明了热波动在溶剂极化中的作用。代替不对称参数的大小,引入分子在该参数上的分布函数。对短泵脉冲产生的弗兰克-康登状态的分析表明,它具有状态的鲜明特征,对于广泛的参数,对称性受到破坏。溶剂极化的热波动显示出对SB至关重要。该理论适用于描述以几种弛豫时间尺度为特征的实际溶剂中SB的动力学。制定了适用于简单得多的固定式SB模型的条件。阐明了热波动在溶剂极化中的作用。代替不对称参数的大小,引入分子在该参数上的分布函数。对短泵脉冲产生的弗兰克-康登状态的分析表明,它具有状态的鲜明特征,对于广泛的参数,对称性受到破坏。溶剂极化的热波动显示出对SB至关重要。该理论适用于描述以几种弛豫时间尺度为特征的实际溶剂中SB的动力学。制定了适用于简单得多的固定式SB模型的条件。阐明了热波动在溶剂极化中的作用。代替不对称参数的大小,引入分子在该参数上的分布函数。对短泵脉冲产生的弗兰克-康登状态的分析表明,它具有状态的鲜明特征,对于广泛的参数,对称性受到破坏。溶剂极化的热波动显示出对SB至关重要。阐明了热波动在溶剂极化中的作用。代替不对称参数的大小,引入分子在该参数上的分布函数。对短泵脉冲产生的弗兰克-康登状态的分析表明,它具有状态的鲜明特征,对于广泛的参数,对称性受到破坏。溶剂极化的热波动显示出对SB至关重要。阐明了热波动在溶剂极化中的作用。代替不对称参数的大小,引入分子在该参数上的分布函数。对短泵脉冲产生的弗兰克-康登状态的分析表明,它具有状态的鲜明特征,对于广泛的参数,对称性受到破坏。溶剂极化的热波动显示出对SB至关重要。
更新日期:2020-11-25
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