Principals of simulation of ultrafast charge transfer in solution within the multichannel stochastic point-transition model

Nazarov, Alexey E.; Федунов, Р. Г.; Ivanov, Anatoly I.

doi:10.1016/j.cpc.2016.09.015

Cited by 17 publications

(10 citation statements)

References 31 publications

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“…In this case, the system of eqs 3 and 4 with the initial condition 20 is solved numerically using the Brownian simulation method. 23,69,70 In the numerical solution, the effective rate constant of ET is determined as…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…In areas where the free energy barrier for a forward reaction is small, the inequalities are not satisfied, and hence, eqs and are not applicable. In this case, the system of eqs and with the initial condition is solved numerically using the Brownian simulation method. ,, In the numerical solution, the effective rate constant of ET is determined as The results of numerical simulations of the ET kinetics are pictured in Figure by dots. Analytical expressions for the rate constants are in a good agreement with the numerical results in the areas of their applicability.…”

Section: Resultsmentioning

confidence: 99%

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Effect of Reactant and Product State Decay on Ultrafast Charge-Transfer Kinetics: Violation of the Principle of Independence of Elementary Chemical Reactions

Михайлова

Ivanov

2017

J. Phys. Chem. C

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Fast decay of both the reactant and product states is shown to strongly increase the intrinsic electron transfer rate in donor−acceptor dyads. The decay is associated with redistribution/ relaxation of excited vibrational states that typically participate in the reaction. Although the role of the reorganization of high-frequency vibrational modes in electron-transfer dynamics is well understood and it is commonly accepted to strongly affect the ultrafast electron transfer dynamics, the influence of the relaxation of excited vibrational states on electron transfer is not accounted for in experimental data analysis. In photoinduced electron transfer, excited states of high-frequency vibrational modes are often produced by laser pump pulse so that the ultrafast charge separation, at least partly, occurs from excited vibrational states. The charge recombination accompanying the charge separation also essentially occurs from excited vibrational states of intermediates to form a final excited vibrational state. Since the decay of the reactant state and electron transfer are two elementary chemical reactions occurring in parallel, the influence of vibrational relaxation on the intrinsic electron-transfer rate constant is a clear manifestation of the violation of the fundamental principle of chemical kinetics postulating the independence of elementary chemical reactions. The mechanism of the violation is discussed in detail. The transition probability that better characterizes the efficiency of ultrafast nonequilibrium charge recombination than the rate constant is calculated. The dependencies of the electron-transfer rate constant and the transition probability on the product decay time are predicted to be identical while on the reactant decay time to be opposite.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Effect of Reactant and Product State Decay on Ultrafast Charge-Transfer Kinetics: Violation of the Principle of Independence of Elementary Chemical Reactions

Михайлова

Ivanov

2017

J. Phys. Chem. C

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“…In what follows, we present the results of their numerical study with the use of the UPTS code. The software employs a basic Brownian algorithm with a special procedure for the reaction event detection and surface hopping (see, e.g., refs , ). Typical simulations involved 10 5 stochastic trajectories to ensure an acceptable level of accuracy.…”

Section: Theory and Computational Detailsmentioning

confidence: 99%

“…These points raise questions about the fundamental possibility of obtaining high CS yields from the second excited state as well as about determining basic characteristics of the molecular systems suitable for efficient photoinduced CT. To clarify the roles of intramolecular and solvent reorganization in these processes and to estimate their effect on the CS efficiency, we employ here a stochastic model of photoinduced CS/CR taking into account both high-frequency quantum intramolecular vibrations and low-frequency classical nuclear relaxation modes with multiple relaxation timescales. This model is studied numerically using the Brownian simulation algorithm with recrossing-detection procedure. − …”

Section: Introductionmentioning

confidence: 99%

The Efficiency of Photoinduced Intramolecular Charge Separation from the Second Excited State: What Factors Can Control It?

2020

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The efficiency of photoinduced charge separation (CS) in electron donor−acceptor compounds is commonly limited due to fast deactivation processes, such as the excited-state internal conversion and ultrafast hot reverse electron transfer to the acceptor, charge recombination (CR). A traditional way to avoid undesired energy losses due to CR is to put the reverse electron transfer into the Marcus inverted region, thus effectively suppressing it. This method, however, is not generally applicable when considering CS from the second locally excited state because the driving force of CR to the first excited state is small, and thus charge recombination is ultrafast and efficient. In this paper, we study the kinetic features of CS/CR from the second locally excited state of the donor using a semiclassical stochastic model of electron transfer. Particular attention is paid to the CS efficiency as well as the influence of the polar environment and intramolecular high-frequency vibrational modes on the kinetics of the charge-separated state. The influence of a number of model parameters on the CS yield and the energy efficiency has been analyzed using the results of numerical simulations. Several simple practical recipes for creating molecular compounds with high CS yields have been suggested. Simulations have also revealed a strong and non-monotonous (double-humped) dependence of both the yield and energy efficiency of CS on the driving force.

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“…The population dynamics is calculated by using the Brownian simulation method . The description of the code can be found in .…”

Section: Model Of Ultrafast Photoinduced Charge Transfermentioning

confidence: 99%

Excitation Frequency Dependence of Ultrafast Photoinduced Charge Transfer Dynamics

Nazarov

Ivanov

2017

Int. J. Chem. Kinet.

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The dependence of the photoinduced charge transfer rate constant on the pump pulse carrier frequency is shown to be strong, and it is considerably affected by the value of the reorganization energy of low-frequency modes at the stage of excitation. In the area of small values of the reorganization energy, the dependence of the charge transfer rate constant on the pump pulse carrier frequency is strongly nonmonotonic that is caused by vibrational resonances and variation of the initial position of the wave packet on the term of the locally excited state. Increasing the reorganization energy smoothes the dependence. The smoothing is caused by the broadening of the vibrational resonances and their overlapping. The highfrequency vibrational mode excitation typically accelerates the charge transfer in both areas of high and low exergonicity and decelerates it in the vicinity of the Marcus barrierless region.

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Principals of simulation of ultrafast charge transfer in solution within the multichannel stochastic point-transition model

Cited by 17 publications

References 31 publications

Effect of Reactant and Product State Decay on Ultrafast Charge-Transfer Kinetics: Violation of the Principle of Independence of Elementary Chemical Reactions

Effect of Reactant and Product State Decay on Ultrafast Charge-Transfer Kinetics: Violation of the Principle of Independence of Elementary Chemical Reactions

The Efficiency of Photoinduced Intramolecular Charge Separation from the Second Excited State: What Factors Can Control It?

Excitation Frequency Dependence of Ultrafast Photoinduced Charge Transfer Dynamics

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