Electronically adiabatic reaction field approach to solvation .2. Solvent effects on electronic spectra
Electronically adiabatic reaction field approach to solvation .2. Solvent effects on electronic spectra
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DOI：
10.1063/1.471831
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发表时间：
1996-10-22
影响因子：
4.4
通讯作者：
Kim, HJ
中科院分区：
文献类型：
--
作者：
Kim, HJ
前一篇文章[H. J. Kim，J.Chem.Phys.105，6818（1996）]通过二阶微扰法分析，并应用于溶液中可极化溶质的静态电子光谱。在Born-Oppenheimer（BO）的溶剂电子极化理论框架下，研究了在任意大小的球形腔和非平衡溶剂取向极化结构中溶质电子的波函数及其自由能级和相关的Franck-Condon（FC）能量.结果表明，溶质的电子结构和自由能随空穴的大小而变化。溶剂化引起的溶质偶极增强随着空腔尺寸的增加而减小。与自洽（SC）反应场理论预测的比较表明，经典的是更有效地极化的溶质比量子表达的BO描述。这是由于后者中存在的分散稳定机制。静态电子光谱研究的线性顺序中的溶质极化率和腔的大小之间的差异，在FC过渡中所涉及的较低和较高的电子状态。在腔尺寸差消失的情况下，将我们对溶剂光谱和斯托克斯位移的分析结果与现有的各种理论进行了比较，并简要讨论了差异的来源。的电子光谱上的腔尺寸的变化的影响示出通过使用一个简单的两态模型描述的溶质。据发现，即使在非极性溶剂中，也可以有一个显着的斯托克斯位移所产生的空腔尺寸弛豫后的FC过渡。此外，腔尺寸波动可以对谱线加宽做出不可忽略的贡献。(C)1996年美国物理学会。
The theoretical formulation developed in the preceding article [H. J. Kim, J. Chem. Phys. 105, 6818 (1996)] is analyzed via a second-order perturbation method and applied to the static electronic spectra of polarizable solutes in solution. In the Born-Oppenheimer (BO) framework of the solvent electronic polarization , the solute electronic wave functions, together with their (free) energy levels and associated Franck-Condon (FC) energies, are examined in the presence of a spherical cavity of arbitrary size and a nonequilibrium solvent orientational polarization configuration . It is found that the solute electronic structure and its free energetics vary strongly with both and the cavity size. The solute dipole enhancement due to solvation decreases with increasing cavity size. Comparison with the self-consistent (SC) reaction field theory predictions shows that classical is more effective in polarizing the solute than quantum couched in the BO description. This is due to the dispersion stabilization mechanism present in the latter. The static electronic spectroscopy is studied to linear order in the solute polarizability and in the cavity size difference between the lower and upper electronic states involved in the FC transition. In the case of the vanishing cavity size difference, our analytic results for the solvent spectral and Stokes shifts are compared with various existing theories and the sources of the discrepancies are briefly discussed. The effects of the cavity size variation on the electronic spectra are illustrated by using a simple two-state model description for the solute. It is found that even in a nonpolar solvent, there can be a significant Stokes shift arising from the cavity size relaxation subsequent to the FC transition. Also the cavity size fluctuations can make a non-negligible contribution to the spectral line broadening. (C) 1996 American Institute of Physics.