Outlines of a theory of proton transfer

Horiuti, Jurô; Polanyi, Michael

doi:10.1016/s1381-1169(03)00034-7

Cited by 39 publications

(33 citation statements)

References 19 publications

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“…This is clear in the founding works, of London [56][57] as well as von Neumann and Wigner [58] for general adiabatic and non-adiabatic reactions, Eyring and Polanyi in the LEP potential-energy surface for reactions [59][60], Horiuti and Polanyi [61] for proton transfer reactions, Wall and Glockler [62] for isomerization reactions like ammonia inversion, and Hush for hydrogen transfer reactions [29]. Central qualitative ideas became imbedded in chemical culture such as symmetry breaking [6,[16][17][18][19][20][63][64][65][66][67], understanding of aromaticity through the concept of resonance energy [68] and Shaik's "twin state" concept [69][70][71][72][73], as well as the reaction force description of classic chemical reactions [74][75][76] Hammond-Leffler postulate [77][78], etc.…”

Section: Related Contentmentioning

confidence: 94%

“…Recognition of the intrinsic relationships involved leads to equations depicting many properties in terms of simple expressions. Shaik's "twin state" concept led to qualitative understanding of various key properties [61,62,63,64,65] but never led to quantitative analysis owing to its misidentification of the actual state that is twin to the ground state.…”

Section: Deducing the CC Bond Lengths In Ethane And Ethylene From Promentioning

confidence: 99%

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Diabatic models with transferrable parameters for generalized chemical reactions

Reimers

McKemmish

McKenzie

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. Diabatic models applied to adiabatic electron-transfer theory yield many equations involving just a few parameters that connect ground-state geometries and vibration frequencies to excited-state transition energies and vibration frequencies to the rate constants for electrontransfer reactions, utilizing properties of the conical-intersection seam linking the ground and excited states through the Pseudo Jahn-Teller effect. We review how such simplicity in basic understanding can also be obtained for general chemical reactions. The key feature that must be recognized is that electron-transfer (or hole transfer) processes typically involve one electron (hole) moving between two orbitals, whereas general reactions typically involve two electrons or even four electrons for processes in aromatic molecules. Each additional moving electron leads to new high-energy but interrelated conical-intersection seams that distort the shape of the critical lowest-energy seam. Recognizing this feature shows how conicalintersection descriptors can be transferred between systems, and how general chemical reactions can be compared using the same set of simple parameters. Mathematical relationships are presented depicting how different conical-intersection seams relate to each other, showing that complex problems can be reduced into an effective interaction between the ground-state and a critical excited state to provide the first semi-quantitative implementation of Shaik's "twin state" concept. Applications are made (i) demonstrating why the chemistry of the firstrow elements is qualitatively so different to that of the second and later rows, (ii) deducing the bond-length alternation in hypothetical cyclohexatriene from the observed UV spectroscopy of benzene, (iii) demonstrating that commonly used procedures for modelling surface hopping based on inclusion of only the first-derivative correction to the Born-Oppenheimer approximation are valid in no region of the chemical parameter space, and (iv), demonstrating the types of chemical reactions that may be suitable for exploitation as a chemical qubit in some quantum information processor. IntroductionThough chemical reactions involve complicated restructuring of the electronic and nuclear configuration and dynamics, it can be useful to use the simplification of envisaging reactions as occurring along a single reaction coordinate. This basic concept forms the conceptual framework of Transition-State Theory and much of modern chemistry. Modern electronic-structure calculation methods can predict wide ranges of properties to within the accuracy of experimental measurements, capturing all chemical and spectroscopic features of the system, but such approaches rarely provide insight into why processes occur and have to be repeated for each small system variation. Diabatic models can be used to interpret these calculations, however, revealing the chemical features controlling the process. Basically, simple forms, called diabatic surfaces, are used to describe the reactants and pro...

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Section: Related Contentmentioning

confidence: 94%

Section: Deducing the CC Bond Lengths In Ethane And Ethylene From Promentioning

confidence: 99%

Diabatic models with transferrable parameters for generalized chemical reactions

Reimers

McKemmish

McKenzie

et al. 2017

J. Phys.: Conf. Ser.

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“…The first treatise on reactivity was by London in 1928 using a diabatic description [111] in which simple potential-energy surfaces described the reactants and the products coupled together to make an adiabatic transition state. The London-EyringPolanyi (LEP) potential-energy surface [112] for general triatomic molecular reactions [113] was extended from this by Eyring and Polanyi in 1931, Horiuti and Polanyi made a similar extension for proton transfer reactions in 1935, [114] Wall and Glocker did the same for isomerization reactions in 1937, [115] and Hush fully generalized it in 1953, considering e.g. redox hydrogen transfer reactions.…”

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confidence: 99%

Putting David Craig’s Legacy to Work in Nanotechnology and Biotechnology

Reimers¹

2016

Aust. J. Chem.

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left us with a lasting legacy concerning basic understanding of chemical spectroscopy and bonding. This is expressed in terms of some of the recent achievements of my own research career, with a focus on integration of Craig's theories with those of Noel Hush to solve fundamental problems in photosynthesis, molecular electronics (particularly in regard to the molecules synthesized by Maxwell Crossley), and self-assembled monolayer structure and function. Reviewed in particular is the relation of Craig's legacy to: the 50-year struggle to assign the visible absorption spectrum of arguably the world's most significant chromophore, chlorophyll; general theories for chemical bonding and structure extending Hush's adiabatic theory of electron-transfer processes; inelastic electron-tunnelling spectroscopy (IETS); chemical quantum entanglement and the Penrose-Hameroff model for quantum consciousness; synthetic design strategies for NMR quantum computing; Gibbs free-energy measurements and calculations for formation and polymorphism of organic self-assembled monolayers on graphite surfaces from organic solution; and understanding the basic chemical processes involved in the formation of gold surfaces and nanoparticles protected by sulfur-bound ligands, ligands whose form is that of Au 0 -thiyl rather than its commonly believed Au I -thiolate tautomer.

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“…[1,4,[19][20][21][22][23][24][25][26] The adiabatic approach is taken in quantum-chemistry packages as this allows the properties of the electrons to be determined at any nuclear configuration. It does not include the effects of nuclear Diabatic model for the energy of a chemical reaction as developed in adiabatic electron-transfer theory but now applied also to general nondissociative chemical reactions.…”

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confidence: 99%

“…From the beginnings of chemical understanding in terms of quantum theory, such a description has been anticipated. [20][21][22][23][24] Indeed, general chemical reactions are often thought of this way, [30,[40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] and there exists a smooth link [55] to the reaction force model [56][57][58] that finds physical insight within reaction energy profiles as a function of the reaction coordinate.…”

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confidence: 99%

The Importance of Motions that Accompany Those Occurring Along the Reaction Coordinate

Reimers

2015

Aust. J. Chem.

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The reaction coordinate is a well known quantity used to define the motions critical to chemical reactions, but many other motions always accompany it. These other motions are typically ignored but this is not always possible. Sometimes it is not even clear as to which motions comprise the reaction coordinate: spectral measurements that one may assume are dominated by the reaction coordinate could instead be dominated by the accompanying modes. Examples of different scenarios are considered. The assignment of the visible absorption spectrum of chlorophyll-a was debated for 50 years, with profound consequences for the understanding of how light energy is transported and harvested in natural and artificial solar-energy devices. We recently introduced a new, comprehensive, assignment, the centrepiece of which was determination of the reaction coordinate for an unrecognized photochemical process. The notion that spectroscopy and reactivity are so closely connected comes directly from Hush's adiabatic theory of electron-transfer reactions. Its basic ideas are reviewed, similarities to traditional chemical theories drawn, key analytical results described, and the importance of the accompanying modes stressed. Also highlighted are recent advances that allow this theory to be applied to general transformations including isomerization processes, hybridization, aromaticity, hydrogen bonding, and understanding why the properties of first-row molecules such as NH 3 (bond angle 1088) are so different to those of PH 3 -BiH 3 (bond angles 90-938). Historically, the question of what is the reaction coordinate and what is just an accompanying motion has not commonly been at the forefront of attention. In our new approach in which all chemical processes are described using the same core theory, this question becomes thrust forward as always being the most important qualitative feature to determine. Chemists mostly consider reactions using a single nuclear coordinate, the reaction coordinate.[1] A simple example of this is apparent in the London-Eyring-Polanyi-Sato [2] (LEPS) potentialenergy surface for the chlorine atom-exchange reaction [3] Clthat is shown in Fig. 1a as a function of the bond lengths R ab and R bc . The reaction coordinate indicates the lowest-energy path that connects reactants to products and is shown in blue in the figure. When a reaction occurs, molecular geometries change holistically, and this coordinate in general is therefore complex, embodying what happens to all atoms including atoms in any solvent or surrounding medium. All other motions are thought to smoothly and perhaps even instantaneously adjust to motion along the reaction coordinate. Fig. 1b displays the energy profile [3] for the chlorine atom-exchange reaction as a function of the reaction coordinate, showing how the energy increases from that at the floor of the reactant valley as the approaching atom gets closer to the molecule, going through a maximum at the reaction's transition state (TS). However, Fig. 1c shows how the distance R ac bet...

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Outlines of a theory of proton transfer

Cited by 39 publications

References 19 publications

Diabatic models with transferrable parameters for generalized chemical reactions

Diabatic models with transferrable parameters for generalized chemical reactions

Putting David Craig’s Legacy to Work in Nanotechnology and Biotechnology

The Importance of Motions that Accompany Those Occurring Along the Reaction Coordinate

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