高等学校化学学报 ›› 2013, Vol. 34 ›› Issue (10): 2247-2253.doi: 10.7503/cjcu20130183

• 学术争鸣 • 上一篇    下一篇

Marcus电子转移理论的科学性探讨

朱晓晴, 杨金东   

  1. 南开大学元素有机化学国家重点实验室, 化学系, 天津 300071
  • 收稿日期:2013-03-01 出版日期:2013-10-10 发布日期:2013-10-10
  • 作者简介:朱晓晴,男,博士,教授,博士生导师,主要从事物理有机化学研究.E-mail:xqzhu@nankai.edu.cn
  • 基金资助:

    国家自然科学基金(批准号:20921120403, 0832004和20721062)和“111计划”项目(批准号:B06005)资助.

Fundamental Flaw of Marcus Theory

ZHU Xiao-Qing, YANG Jin-Dong   

  1. State Key Laboratory of Elemento-Organic Chemistry, Department of Chemistry, Nankai University, Tianjin 300071, China
  • Received:2013-03-01 Online:2013-10-10 Published:2013-10-10

摘要:

利用科学原理对Marcus电子转移理论的科学性进行了考察, 结果表明Marcus电子转移理论违背了能量守恒定律.

关键词: 电子转移反应, Marcus电子转移理论, 非平衡态, 溶剂极化

Abstract:

Marcus theory is a theory originally developed by Rudolph A. Marcus in 1956 based on Libby's idea about electron transfer mechanism according to the two-sphere model with the help of the continuous medium theory and the electrostatic mechanics to describe the kinetics of the outer-sphere electron transfer reactions in solution, which states that the activation free energies of the outer-sphere electron transfer reactions have the quadratic relationship with the corresponding reaction free energy changes. Having been developed by Marcus and many other chemists for more than 50 years, Marcus theory has received extensive application in various fields. Meanwhile, the research object of Marcus theory has been extended from the outer-sphere electron transfer reactions to the inner-sphere electron transfer reactions, even more to the nucleus transfer reactions. Because the reaction coordinates of the transition state of the electron transfer reactions in Marcus inverted region go beyond the region between the initial state and the final state of the reactions in the same reaction coordinate system, which evidently does not obey the natural change logic, we have never accepted Marcus theory as a scientific theory, even though some experimental observations were reported by Miller and Closs as well as many other chemists to support Marcus inverted region. In order to dig out the origin of Marcus theory error, in this study we examined the following questions about the classical Marcus theory:(1) What are the prerequisites(or assumptions) of Marcus theory? (2) How do Marcus free energy parabolas for the reactant system and for the product system form? (3) What factors determine the feature of Marcus free energy parabolas? (4) How does the classical Marcus equation form? (5) What is the criterion of Marcus inverted region? After the examinations, the following conclusions can be made:(1) Marcus theory directly conflicts with the law of conservation of energy and has the error in principle; (2) Marcus inverted region is impossible; (3) the experimental observations for Marcus inverted region reported in the literatures are all spurious.

Key words: Electron transfer reaction, Marcus theory, Non-equilibrium state, Solvent polarization

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