کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9575133 | 1504340 | 2005 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Molecular simulations of outersphere reorganization energies for intramolecular electron and hole transfer in polar solvents
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
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![عکس صفحه اول مقاله: Molecular simulations of outersphere reorganization energies for intramolecular electron and hole transfer in polar solvents Molecular simulations of outersphere reorganization energies for intramolecular electron and hole transfer in polar solvents](/preview/png/9575133.png)
چکیده انگلیسی
Outersphere reorganization energies (λ) for intramolecular electron transfer (ET) and hole transfer are studied in anion- and cation-radical forms of complex organic substrates (biphenylyl-spacer-naphtyl) in polar solvents simulated by means of the nonpolarizable models of water and 1,2-dichloroethane. The earlier elaborated molecular/continuum approach (the MD/FRCM, J. Chem. Phys., 119 (2003) 8024) is used; this method provides a physically relevant background for separating inertial and inertialess polarization responses within a nonpolarizable MD simulation (the SPC water model). Quantum-chemical calculations of solute charge distributions were performed with semiempirical (AM1) and second ab initio (HF/6-31G(d,p)) approximations. Ab initio charges give lower λ-values and are preferable, probably, because of including the effect of the SCRF polarization of the diabatic ET states. Standard Lennard-Jones and charge parameters implemented in MD runs were not specially fitted for reproducing ET effects. The difference in values for a cation and an anion originating from the same parent structure was specially investigated. As shown earlier, this effect, nonlinear in its nature, proved to be extremely large when a model dipolar two-site system was studied. For the present ET structures representing real chemical substrates it has reduced to a plausible value of 6-8 kcal/mol. The study of the temperature dependence of λ comprises a first MD simulation of this problem and its slope was found to be in accord with an experimental observation for an anionic species. Calculations of absolute λ-values for the hole transfer in 1,2-dichloroethane are the first MD simulations of reorganization energies in experimentally studied reactions. Computed values of λ-s are higher than the experimental data. The effect of this magnitude could be eliminated by proper tuning the solvent parameters.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 319, Issues 1â3, 7 December 2005, Pages 4-15
Journal: Chemical Physics - Volume 319, Issues 1â3, 7 December 2005, Pages 4-15
نویسندگان
I.V. Leontyev, A.V. Tovmash, M.V. Vener, I.V. Rostov, M.V. Basilevsky,