Adiabatic versus Non‐Adiabatic Electron Transfer

Sumi, Hitoshi

doi:10.1002/9783527618248.ch2

Cited by 17 publications

(16 citation statements)

References 41 publications

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“…The non-adiabatic ET rate in the high-temperature regime can be written (see details in ESI Section III.4 † and ref. 36 ): k ET = = 〈transition velocity〉 × 〈density of states at curve crossing per unit length〉transition velocity = 〈transition velocity〉 × 〈density of states at curve crossing per unit length〉 × = 〈transition velocity〉 × 〈density of states at curve crossing per unit length〉density of states at curve crossing per unit length = 〈transition velocity〉 × 〈density of states at curve crossing per unit length〉 ξ is the reaction coordinate, and the donor and acceptor potential energy surfaces cross at ξ = ξ x .…”

Section: Ir-induced Et Rate Modulation Mechanismsmentioning

confidence: 99%

How can infra-red excitation both accelerate and slow charge transfer in the same molecule?

Lin

Lawrence

et al. 2018

Chem. Sci.

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Section: Ir-induced Et Rate Modulation Mechanismsmentioning

confidence: 99%

How can infra-red excitation both accelerate and slow charge transfer in the same molecule?

Lin

Lawrence

et al. 2018

Chem. Sci.

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“…Due to different recrossing possibilities, the reaction yield depends differently on the transition probability P LZ in the normal and abnormal regions, − where the first derivatives F 1 and F 2 have different and the same signs, respectively: The Landau–Zener pre-exponent is calculated by averaging over the thermal Maxwell–Boltzmann distribution of velocities: − where ω denotes the effective frequency along the reaction coordinate near the reactant minimum. As shown in the Supporting Information, the adiabatic and nonadiabatic limits , of eq in the normal region are equal to the adiabatic transition state theory (TST) pre-exponent, ν TST = ω/2π, and the Fermi golden rule (FGR) pre-exponent, ν FGR ∝ V 2 , respectively. Figure depicts the dependence of the pre-exponent on the vibronic coupling V and solvent relaxation time τ L .…”

mentioning

confidence: 99%

Kinetics of Proton Discharge on Metal Electrodes: Effects of Vibrational Nonadiabaticity and Solvent Dynamics

Lam

Soudackov

Hammes‐Schiffer

2019

J. Phys. Chem. Lett.

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Proton discharge on metal electrodes, also denoted the Volmer reaction, is a critical step in a wide range of electrochemical processes. This electrochemical proton-coupled electron transfer (PCET) reaction is predominantly electronically adiabatic in aqueous solution and is typically treated as fully adiabatic. Recently, a theoretical model for this PCET reaction was developed to generate the vibronic free energy surfaces as functions of a collective solvent coordinate and the distance of the proton-donating acid from the electrode. Herein a unified formulation is devised to describe such PCET reactions in terms of a curve crossing between two diabatic vibronic states corresponding to the lowest two proton vibrational states, employing an interpolation scheme that spans the adiabatic transition state theory, nonadiabatic Fermi golden rule, and solvent-controlled regimes. In contrast to previous treatments, application of this formulation to the aqueous Volmer reaction highlights the importance of vibrational nonadiabaticity and solvent dynamics. The calculated transfer coefficients and kinetic isotope effects are in reasonable agreement with experimental measurements. These fundamental insights have broad implications for understanding electrochemical processes.

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“…In the non‐adiabatic (diabatic) limit, the pre‐exponential factor will decrease exponentially with the distance of the reactive species from the electrode, but will be independent of solvent relaxation time. In the intermediary regime, the rate constant will depend on both processes . However, the determination of the magnitude of the electronic coupling of a molecule to a bare electrode surface is far from easy and the question about the adiabaticity of the heterogeneous ET is controversial .…”

Section: Resultsmentioning

confidence: 99%

Towards Understanding the Solvent‐Dynamic Control of the Transport and Heterogeneous Electron‐Transfer Processes in Ionic Liquids

2017

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The impact of temperature-induced changes in solvent dynamics on the diffusion coefficient and standard rate constant k for heterogeneous electron transfer (ET) of ethylferrocene (EFc) in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF ]) is investigated. The results are analysed to understand the impact of solvent-dynamic control, solute-solvent interactions and solvent friction on the transport of redox probes and k . Concentration dependence of the diffusion coefficient of EFc in [BMIM][PF ] is observed. This is attributed to the solute-induced enhancement of the structural organisation of the ionic liquid (IL), which is supported by the concentration-dependent UV/Vis absorption and photoluminescence responses of EFc/[BMIM][PF ] solutions. Similar values of the activation energies for mass transport and ET and a linear relationship between the diffusion coefficient and the heterogeneous ET rate is observed. The ratio between the diffusion coefficient and the heterogeneous rate constant allows a characteristic length L , which is temperature-independent, to be introduced. The presented results clearly establish that mass transport and heterogeneous ET of redox probes are strongly correlated in ILs. It is proposed that the apparent kinetics of heterogeneous ET reactions in ILs can be explained in terms of their impact on thermal equilibration, energy dissipation and thermal excitation of redox-active probes.

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Adiabatic versus Non‐Adiabatic Electron Transfer

Cited by 17 publications

References 41 publications

How can infra-red excitation both accelerate and slow charge transfer in the same molecule?

How can infra-red excitation both accelerate and slow charge transfer in the same molecule?

Kinetics of Proton Discharge on Metal Electrodes: Effects of Vibrational Nonadiabaticity and Solvent Dynamics

Towards Understanding the Solvent‐Dynamic Control of the Transport and Heterogeneous Electron‐Transfer Processes in Ionic Liquids

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