1
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Kaufman B, Marquetand P, Rozgonyi T, Weinacht T. Long-Lived Electronic Coherences in Molecules. PHYSICAL REVIEW LETTERS 2023; 131:263202. [PMID: 38215370 DOI: 10.1103/physrevlett.131.263202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/29/2023] [Accepted: 11/01/2023] [Indexed: 01/14/2024]
Abstract
We demonstrate long-lived electronic coherences in molecules using a combination of measurements with shaped octave spanning ultrafast laser pulses and calculations of the light matter interaction. Our pump-probe measurements prepare and interrogate entangled nuclear-electronic wave packets whose electronic phase remains well defined despite vibrational motion along many degrees of freedom. The experiments and calculations illustrate how coherences between excited states can survive, even when coherence with the ground state is lost, and may have important implications for many areas of attosecond science and photochemistry.
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Affiliation(s)
- Brian Kaufman
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA
| | - Philipp Marquetand
- University of Vienna, Faculty of Chemistry, Institute of Theoretical Chemistry, Währinger Strasse 17, 1090 Wien, Austria
| | - Tamás Rozgonyi
- Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary
| | - Thomas Weinacht
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA
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2
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Gustin I, Kim CW, McCamant DW, Franco I. Mapping electronic decoherence pathways in molecules. Proc Natl Acad Sci U S A 2023; 120:e2309987120. [PMID: 38015846 PMCID: PMC10710033 DOI: 10.1073/pnas.2309987120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 10/25/2023] [Indexed: 11/30/2023] Open
Abstract
Establishing the fundamental chemical principles that govern molecular electronic quantum decoherence has remained an outstanding challenge. Fundamental questions such as how solvent and intramolecular vibrations or chemical functionalization contribute to the decoherence remain unanswered and are beyond the reach of state-of-the-art theoretical and experimental approaches. Here we address this challenge by developing a strategy to isolate electronic decoherence pathways for molecular chromophores immersed in condensed phase environments that enables elucidating how electronic quantum coherence is lost. For this, we first identify resonance Raman spectroscopy as a general experimental method to reconstruct molecular spectral densities with full chemical complexity at room temperature, in solvent, and for fluorescent and non-fluorescent molecules. We then show how to quantitatively capture the decoherence dynamics from the spectral density and identify decoherence pathways by decomposing the overall coherence loss into contributions due to individual molecular vibrations and solvent modes. We illustrate the utility of the strategy by analyzing the electronic decoherence pathways of the DNA base thymine in water. Its electronic coherences decay in [Formula: see text]30 fs. The early-time decoherence is determined by intramolecular vibrations while the overall decay by solvent. Chemical substitution of thymine modulates the decoherence with hydrogen-bond interactions of the thymine ring with water leading to the fastest decoherence. Increasing temperature leads to faster decoherence as it enhances the importance of solvent contributions but leaves the early-time decoherence dynamics intact. The developed strategy opens key opportunities to establish the connection between molecular structure and quantum decoherence as needed to develop chemical strategies to rationally modulate it.
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Affiliation(s)
- Ignacio Gustin
- Department of Chemistry, University of Rochester, Rochester, NY14627
| | - Chang Woo Kim
- Department of Chemistry, Chonnam National University, Gwangju61186, South Korea
| | - David W. McCamant
- Department of Chemistry, University of Rochester, Rochester, NY14627
| | - Ignacio Franco
- Department of Chemistry, University of Rochester, Rochester, NY14627
- Department of Physics, University of Rochester, Rochester, NY14627
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3
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Zhang B, Shuai Z. Quantum Dynamical Approach to Predicting the Optical Pumping Threshold for Lasing in Organic Materials. J Phys Chem Lett 2023; 14:8590-8598. [PMID: 37726254 DOI: 10.1021/acs.jpclett.3c02171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
The quantum dynamic (QD) study of organic lasing (OL) is a challenging issue in organic optoelectronics. Previously, the phenomenological method has achieved success in describing experimental observation. However, it cannot directly bridge the laser threshold (LT) with microscopic parameters, which is the advantage of the QD method. In this paper, we propose a microscopic OL model and apply time-dependent wave packet diffusion to reveal the microscopic QD process of optically pumped lasing. LT is obtained from the onset of output as a function of optical input pumping. We predict that the LT has an optimal value as a function of the cavity volume and depends linearly on the intracavity photon leakage rate. The calculated structure-property relationships between molecular parameters and the LT are in qualitative agreement with the experimental results, confirming the reliability of our approach. This work is beneficial for understanding the OL mechanism and optimizing the design of organic laser materials.
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Affiliation(s)
- Bin Zhang
- MOE Key Laboratory of Organic OptoElectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Zhigang Shuai
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, P. R. China
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4
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Shu Y, Truhlar DG. Decoherence and Its Role in Electronically Nonadiabatic Dynamics. J Chem Theory Comput 2023; 19:380-395. [PMID: 36622843 PMCID: PMC9878713 DOI: 10.1021/acs.jctc.2c00988] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Indexed: 01/10/2023]
Abstract
Decoherence is the tendency of a time-evolved reduced density matrix for a subsystem to assume a form corresponding to a statistical ensemble of states rather than a coherent combination of pure-state wave functions. When a molecular process involves changes in the electronic state and the coordinates of the nuclei, as in ultraviolet or visible light photochemistry or electronically inelastic collisions, the reduced density matrix of the electronic subsystem suffers decoherence, due to its interaction with the nuclear subsystem. We present the background necessary to conceptualize this decoherence; in particular, we discuss the density matrix description of pure states and mixed states, and we discuss pointer states and decoherence time. We then discuss how decoherence is treated in the coherent switching with decay of mixing algorithm and the trajectory surface hopping method for semiclassical calculations of electronically nonadiabatic processes.
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Affiliation(s)
- Yinan Shu
- Department of Chemistry,
Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota55455-0431, United States
| | - Donald G. Truhlar
- Department of Chemistry,
Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota55455-0431, United States
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5
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Hu W, Gustin I, Krauss TD, Franco I. Tuning and Enhancing Quantum Coherence Time Scales in Molecules via Light-Matter Hybridization. J Phys Chem Lett 2022; 13:11503-11511. [PMID: 36469838 PMCID: PMC9761670 DOI: 10.1021/acs.jpclett.2c02877] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023]
Abstract
Protecting quantum coherences in matter from the detrimental effects introduced by its environment is essential to employ molecules and materials in quantum technologies and develop enhanced spectroscopies. Here, we show how dressing molecular chromophores with quantum light in the context of optical cavities can be used to generate quantum superposition states with tunable coherence time scales that are longer than those of the bare molecule, even at room temperature and for molecules immersed in solvent. For this, we develop a theory of decoherence rates for molecular polaritonic states and demonstrate that quantum superpositions that involve such hybrid light-matter states can survive for times that are orders of magnitude longer than those of the bare molecule while remaining optically controllable. Further, by studying these tunable coherence enhancements in the presence of lossy cavities, we demonstrate that they can be enacted using present-day optical cavities. The analysis offers a viable strategy to engineer and increase quantum coherence lifetimes in molecules.
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Affiliation(s)
- Wenxiang Hu
- Materials
Science Program, University of Rochester, Rochester, New York14627, United States
| | - Ignacio Gustin
- Department
of Chemistry, University of Rochester, Rochester, New York14627, United States
| | - Todd D. Krauss
- Department
of Chemistry, University of Rochester, Rochester, New York14627, United States
- Institute
of Optics, University of Rochester, Rochester, New York14627, United States
| | - Ignacio Franco
- Department
of Chemistry, University of Rochester, Rochester, New York14627, United States
- Department
of Physics, University of Rochester, Rochester, New York14627, United States
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6
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Kananenka AA, Strong SE, Skinner JL. Dephasing and Decoherence in Vibrational and Electronic Line Shapes. J Phys Chem B 2020; 124:1531-1542. [PMID: 31990552 DOI: 10.1021/acs.jpcb.9b11655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Absorption and emission line shapes of vibrational and electronic transitions in liquids are broadened by interactions with the "bath" (in this case, the rotational and translational degrees of freedom of all the molecules in the liquid). If these degrees of freedom are treated classically, the broadening process is often known as dephasing. If, on the other hand, the bath degrees of freedom are instead treated quantum mechanically, there is additional broadening due to what is known in the chemical-physics literature as decoherence. The question addressed in this paper is the relative importance of decoherence (bath quantum effects) and dephasing. We present general developments of this subject for absorption and emission line shapes, discover several new relationships connecting classical and quantum treatments of the bath, and also consider the Stokes shift (difference in peak frequencies in absorption and emission). We next draw some general conclusions by considering a model system whose transition-frequency time-correlation function has only one bath time scale. We then consider a realistic system of the vibrational OH stretch transition of dilute HOD in liquid D2O at room temperature. For this system, we conclude that bath quantum effects are not very important, except for the Stokes shift. More generally, we argue that this is the case for many vibrational and most electronic transitions in room-temperature liquids.
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Affiliation(s)
- Alexei A Kananenka
- Pritzker School of Molecular Engineering , The University of Chicago , Chicago , Illinois 60637 , United States.,Department of Physics and Astronomy , University of Delaware , Newark , Delaware 19716 , United States
| | - Steven E Strong
- Pritzker School of Molecular Engineering , The University of Chicago , Chicago , Illinois 60637 , United States
| | - J L Skinner
- Pritzker School of Molecular Engineering , The University of Chicago , Chicago , Illinois 60637 , United States
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7
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Gu B, Franco I. Electronic interactions do not affect electronic decoherence in the pure-dephasing limit. J Chem Phys 2018; 149:174115. [PMID: 30408977 DOI: 10.1063/1.5049710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The relationship between electronic interactions and electronic decoherence is a fundamental problem in chemistry. Here we show that varying the electron-electron interactions does not affect the electronic decoherence in the pure-dephasing limit. In this limit, the effect of varying the electronic interactions is to rigidly shift in energy the diabatic potential energy surfaces without changing their shape, thus keeping the nuclear dynamics in these surfaces that leads to the electronic decoherence intact. This analysis offers a simple and intuitive understanding of previous theoretical and computational efforts to characterize the influence of electronic interactions on the decoherence and opens opportunities to study exact electronic decoherence with approximate electronic structure theories.
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Affiliation(s)
- Bing Gu
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
| | - Ignacio Franco
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
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8
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Multidimensional Vibrational Coherence Spectroscopy. Top Curr Chem (Cham) 2018; 376:35. [DOI: 10.1007/s41061-018-0213-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/31/2018] [Indexed: 10/28/2022]
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9
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Jonas DM. Vibrational and Nonadiabatic Coherence in 2D Electronic Spectroscopy, the Jahn–Teller Effect, and Energy Transfer. Annu Rev Phys Chem 2018; 69:327-352. [DOI: 10.1146/annurev-physchem-052516-050602] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- David M. Jonas
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
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10
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Gu B, Franco I. Generalized Theory for the Timescale of Molecular Electronic Decoherence in the Condensed Phase. J Phys Chem Lett 2018; 9:773-778. [PMID: 29343064 DOI: 10.1021/acs.jpclett.7b03322] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We introduce a general theory of electronic decoherence for molecules in the condensed phase that captures contributions coming from pure dephasing effects, electronic transitions among diabatic states, and their interference. The theory is constructed by taking advantage of a recently developed [ J. Phys. Chem. Lett. 2017 , 8 , 4289 - 4294 ] general expression for decoherence times that is based on an early time expansion of the purity dynamics and extends early electronic decoherence models based on pure dephasing ideas. Using this theory, we construct the decoherence time for the displaced harmonic oscillator model amended with constant and linear diabatic couplings, which is a widely used model of the photoexcited dynamics of molecules. The validity of the short-time expansion is demonstrated by the quantitative agreement of the theory with exact numerical computations of the decoherence dynamics obtained using the hierarchical equation of motion method. These developments offer a rigorous understanding of early time electronic decoherence processes that accompany basic molecular events and demonstrate that electronic transitions among diabatic states play a major role in the decoherence dynamics.
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Affiliation(s)
- Bing Gu
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Ignacio Franco
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
- Department of Physics, University of Rochester , Rochester, New York 14627, United States
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11
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Mannouch JR, Barford W, Al-Assam S. Ultra-fast relaxation, decoherence, and localization of photoexcited states in π-conjugated polymers. J Chem Phys 2018; 148:034901. [DOI: 10.1063/1.5009393] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jonathan R. Mannouch
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
- University College, University of Oxford, Oxford OX1 4BH, United Kingdom
| | - William Barford
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Sarah Al-Assam
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
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12
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Tiwari V, Peters WK, Jonas DM. Electronic energy transfer through non-adiabatic vibrational-electronic resonance. I. Theory for a dimer. J Chem Phys 2017; 147:154308. [DOI: 10.1063/1.5005835] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Vivek Tiwari
- Department of Chemistry and Biochemistry, University of Colorado, 215 UCB, Boulder, Colorado 80309, USA
| | - William K. Peters
- Department of Chemistry and Biochemistry, University of Colorado, 215 UCB, Boulder, Colorado 80309, USA
| | - David M. Jonas
- Department of Chemistry and Biochemistry, University of Colorado, 215 UCB, Boulder, Colorado 80309, USA
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13
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14
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Mallus MI, Schallwig M, Kleinekathöfer U. Relation between Vibrational Dephasing Time and Energy Gap Fluctuations. J Phys Chem B 2017. [PMID: 28625060 DOI: 10.1021/acs.jpcb.7b02693] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dephasing processes are present in basically all applications in which quantum mechanics plays a role. These applications certainly include excitation energy and charge transfer in biological systems. In a previous study, we have analyzed the vibrational dephasing time as a function of energy gap fluctuation for a large set of molecular simulations. In that investigation, individual molecular subunits were the focus of the calculations. The set of studied molecules included bacteriochlorophylls in Fenna-Matthews-Olson and light-harvesting system 2 complexes as well as bilins in PE545 aggregates. The present work extends this study to entire complexes, including the respective intermolecular couplings. Again, it can be concluded that a universal and inverse proportionality exists between dephasing time and variance of the excitonic energy gap fluctuations, whereas the respective proportionality constants can be rationalized using the energy gap autocorrelation functions. Furthermore, these findings can be extended to the gaps between higher-lying neighboring excitonic states.
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Affiliation(s)
- Maria Ilaria Mallus
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | - Maximilian Schallwig
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
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15
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Kar A, Franco I. Quantifying fermionic decoherence in many-body systems. J Chem Phys 2017; 146:214107. [PMID: 28595395 PMCID: PMC5648582 DOI: 10.1063/1.4984128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/13/2017] [Indexed: 01/01/2023] Open
Abstract
Practical measures of electronic decoherence, called distilled purities, that are applicable to many-body systems are introduced. While usual measures of electronic decoherence such as the purity employ the full N-particle density matrix which is generally unavailable, the distilled purities are based on the r-body reduced density matrices (r-RDMs) which are more accessible quantities. The r-body distilled purities are derivative quantities of the previously introduced r-body reduced purities [I. Franco and H. Appel, J. Chem. Phys. 139, 094109 (2013)] that measure the non-idempotency of the r-RDMs. Specifically, the distilled purities exploit the structure of the reduced purities to extract coherences between Slater determinants with integer occupations defined by a given single-particle basis that compose an electronic state. In this way, the distilled purities offer a practical platform to quantify coherences in a given basis that can be used to analyze the quantum dynamics of many-electron systems. Exact expressions for the one-body and two-body distilled purities are presented and the utility of the approach is exemplified via an analysis of the dynamics of oligo-acetylene as described by the Su-Schrieffer-Heeger Hamiltonian. Last, the advantages and limitations of the purity, reduced purity, and distilled purity as measures of electronic coherence are discussed.
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Affiliation(s)
- Arnab Kar
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
| | - Ignacio Franco
- Department of Chemistry, University of Rochester, Rochester, New York 14627, USA
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16
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Shirmovsky SE. Quantum dynamics of a hole migration through DNA: A single strand DNA model. Biophys Chem 2016; 217:42-57. [PMID: 27497061 DOI: 10.1016/j.bpc.2016.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 07/05/2016] [Accepted: 07/17/2016] [Indexed: 11/24/2022]
Abstract
A model predicting the behavior of a hole acting on the DNA strand was investigated. The hole-DNA interaction on the basis of a quantum-classical, non-linear DNA single strand model was described. The fact that a DNA molecule is formed by a furanose ring as its sugar, phosphate group and bases was taken into consideration. Based on the model, results were obtained for the probability of a hole location on the DNA base sequences, such as GTTGGG, GATGTGGG, GTTGTTGGG as well as on the sugar-phosphate groups mated with them.
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Affiliation(s)
- S Eh Shirmovsky
- Far Eastern Federal University, 8 Sukhanov St., Vladivostok 690950, Russia.
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17
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Kar A, Chen L, Franco I. Understanding the Fundamental Connection Between Electronic Correlation and Decoherence. J Phys Chem Lett 2016; 7:1616-1621. [PMID: 27075605 DOI: 10.1021/acs.jpclett.6b00467] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We introduce a theory that exposes the fundamental and previously overlooked connection between the correlation among electrons and the degree of quantum coherence of electronic states in matter. For arbitrary states, the effects only decouple when the electronic dynamics induced by the nuclear bath is pure-dephasing in nature such that [H(S),H(SB)] = 0, where H(S) is the electronic Hamiltonian and H(SB) is the electron-nuclear coupling. We quantitatively illustrate this connection via exact simulations of a Hubbard-Holstein molecule using the Hierarchical Equations of Motion that show that increasing the degree of electronic interactions can enhance or suppress the rate of electronic coherence loss.
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Affiliation(s)
- Arnab Kar
- Department of Chemistry and The Center for Coherence and Quantum Optics, University of Rochester , Rochester, New York 14627, United States
| | - Liping Chen
- Department of Chemistry and The Center for Coherence and Quantum Optics, University of Rochester , Rochester, New York 14627, United States
| | - Ignacio Franco
- Department of Chemistry and The Center for Coherence and Quantum Optics, University of Rochester , Rochester, New York 14627, United States
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18
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Mallus MI, Aghtar M, Chandrasekaran S, Lüdemann G, Elstner M, Kleinekathöfer U. Relation between Dephasing Time and Energy Gap Fluctuations in Biomolecular Systems. J Phys Chem Lett 2016; 7:1102-1108. [PMID: 26950038 DOI: 10.1021/acs.jpclett.6b00134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Excitation energy and charge transfer are fundamental processes in biological systems. Because of their quantum nature, the effect of dephasing on these processes is of interest especially when trying to understand their efficiency. Moreover, recent experiments have shown quantum coherences in such systems. As a first step toward a better understanding, we studied the relationship between dephasing time and energy gap fluctuations of the individual molecular subunits. A larger set of molecular simulations has been investigated to shed light on this dependence. This set includes bacterio-chlorophylls in Fenna-Matthews-Olson complexes, the PE545 aggregate, the LH2 complexes, DNA, photolyase, and cryptochromes. For the individual molecular subunits of these aggregates it has been confirmed quantitatively that an inverse proportionality exists between dephasing time and average gap energy fluctuation. However, for entire complexes including the respective intermolecular couplings, such a relation still needs to be verified.
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Affiliation(s)
- Maria Ilaria Mallus
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | - Mortaza Aghtar
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | | | - Gesa Lüdemann
- Institute of Physical Chemistry, Karlsruhe Institute of Technology , 76131 Karlsruhe, Germany
| | - Marcus Elstner
- Institute of Physical Chemistry, Karlsruhe Institute of Technology , 76131 Karlsruhe, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
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19
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Narth C, Gillet N, Cailliez F, Lévy B, de la Lande A. Electron transfer, decoherence, and protein dynamics: insights from atomistic simulations. Acc Chem Res 2015; 48:1090-7. [PMID: 25730126 DOI: 10.1021/ar5002796] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electron transfer in biological systems drives the processes of life. From cellular respiration to photosynthesis and enzymatic catalysis, electron transfers (ET) are chemical processes on which essential biological functions rely. Over the last 40 years, scientists have sought understanding of how these essential processes function in biology. One important breakthrough was the discovery that Marcus theory (MT) of electron transfer is applicable to biological systems. Chemists have experimentally collected both the reorganization energies (λ) and the driving forces (ΔG°), two parameters of Marcus theory, for a large variety of ET processes in proteins. At the same time, theoretical chemists have developed computational approaches that rely on molecular dynamics and quantum chemistry calculations to access numerical estimates of λ and ΔG°. Yet another crucial piece in determining the rate of an electron transfer is the electronic coupling between the initial and final electronic wave functions. This is an important prefactor in the nonadiabatic rate expression, since it reflects the probability that an electron tunnels from the electron donor to the acceptor through the intervening medium. The fact that a protein matrix supports electron tunneling much more efficiently than vacuum is now well documented, both experimentally and theoretically. Meanwhile, many chemists have provided examples of the rich physical chemistry that can be induced by protein dynamics. This Account describes our studies of the dynamical effects on electron tunneling. We present our analysis of two examples of natural biological systems through MD simulations and tunneling pathway analyses. Through these examples, we show that protein dynamics sustain efficient tunneling. Second, we introduce two time scales: τcoh and τFC. The former characterizes how fast the electronic coupling varies with nuclear vibrations (which cause dephasing). The latter reflects the time taken by the system to leave the crossing region. In the framework of open quantum systems, τFC is a short time approximation of the characteristic decoherence time of the electronic subsystem in interaction with its nuclear environment. The comparison of the respective values of τcoh and τFC allows us to probe the occurrence of non-Condon effects. We use ab initio MD simulations to analyze how decoherence appears in several biological cofactors. We conclude that we cannot account for its order of magnitude by considering only the atoms or bonds directly concerned with the transfer. Decoherence results from contributions from all atoms of the system appearing with a time delay that increases with the distance from the primarily concerned atoms or bonds. The delay and magnitude of the contributions depend on the chemical nature of the system. Finally, we present recent developments based on constrained DFT for efficient and accurate evaluations of the electronic coupling in ab initio MD simulations. These are promising methods to study the subtle fluctuations of the electronic coupling and the mechanisms of electronic decoherence in biological systems.
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Affiliation(s)
- Christophe Narth
- Laboratoire
de Chimie Théorique, CNRS UMR 7616, Université Pierre et Marie Curie, case courrier 137. 4, Place Jussieu, 75252 Cedex 05 Paris, France
| | - Natacha Gillet
- Laboratoire
de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment
349 - Campus d’Orsay. 15, avenue Jean Perrin, 91405 Cedex Orsay, France
| | - Fabien Cailliez
- Laboratoire
de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment
349 - Campus d’Orsay. 15, avenue Jean Perrin, 91405 Cedex Orsay, France
| | - Bernard Lévy
- Laboratoire
de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment
349 - Campus d’Orsay. 15, avenue Jean Perrin, 91405 Cedex Orsay, France
| | - Aurélien de la Lande
- Laboratoire
de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment
349 - Campus d’Orsay. 15, avenue Jean Perrin, 91405 Cedex Orsay, France
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20
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Franco I, Appel H. Reduced purities as measures of decoherence in many-electron systems. J Chem Phys 2013; 139:094109. [PMID: 24028104 DOI: 10.1063/1.4819819] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A hierarchy of measures of decoherence for many-electron systems that is based on the purity and the hierarchy of reduced electronic density matrices is presented. These reduced purities can be used to characterize electronic decoherence in the common case when the many-body electronic density matrix is not known and only reduced information about the electronic subsystem is available. Being defined from reduced electronic quantities, the interpretation of the reduced purities is more intricate than the usual (many-body) purity. This is because the nonidempotency of the r-body reduced electronic density matrix that is the basis of the reduced purity measures can arise due to decoherence or due to electronic correlations. To guide the interpretation, explicit expressions are provided for the one-body and two-body reduced purities for a general electronic state. Using them, the information content and structure of the one-body and two-body reduced purities is established, and limits on the changes that decoherence can induce are elucidated. The practical use of the reduced purities to understand decoherence dynamics in many-electron systems is exemplified through an analysis of the electronic decoherence dynamics in a model molecular system.
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Affiliation(s)
- Ignacio Franco
- Theory Department, Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany
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21
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Shirmovsky SE, Boyda DL. Study of DNA conducting properties: reversible and irreversible evolution. Biophys Chem 2013; 180-181:95-101. [PMID: 23911953 DOI: 10.1016/j.bpc.2013.06.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 06/18/2013] [Accepted: 06/18/2013] [Indexed: 11/19/2022]
Abstract
A hole transport through DNA base sequences was modeled. The fact that DNA consists of two polynucleotide strands was taken into consideration. Specific DNA base locations are determined in the model. The model predicts the behavior of a hole acting on the DNA chain, taking into account reversible and irreversible dynamics. It was shown that the transfer mechanisms depend on the sequence type and can be either of hopping nature or of superexchange one. Distance dependence of the hole transport relative rate on the number of hopping steps was investigated. The results obtained were compared with the experimental data. The investigation demonstrates the utilization of the formalism in practical problems for description of the charge migration through the different molecular sequences.
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Affiliation(s)
- S Eh Shirmovsky
- Theoretical and Experimental Physics Cathedra, Far Eastern Federal University, 8 Sukhanov St., Vladivostok 690950, Russia.
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Song J, Liu Y. Theoretical Study on Optical Properties of Oligofluorenes. CHINESE J CHEM PHYS 2013. [DOI: 10.1063/1674-0068/26/04/409-414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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23
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Narth C, Gillet N, Lévy B, Demachy I, de la Lande A. Investigation of the molecular mechanisms of electronic decoherence within a quinone cofactor. CAN J CHEM 2013. [DOI: 10.1139/cjc-2012-0529] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The notion of decoherence is particularly adapted to discuss the quantum-to-classical transition in the context of chemical reactions. Decoherence can be modeled by computing the time evolution of nuclear wave packets evolving on distinct potential energy surfaces, here using density functional theory (DFT) and Born–Oppenheimer molecular dynamics simulations. We investigate a redox cofactor of biological interest (tryptophan tryptophylquinone, TTQ) found in the enzyme methylamine dehydrogenase. We also report the first systematic comparison of semi-empirical DFT (tight-binding DFT) and classical force field approaches for estimating decoherence in molecular systems. In the TTQ cofactor, we find that decoherence combines structural and dynamical aspects: it is initiated by the divergent motions of few atoms and then propagates dynamically to the remaining atoms. It is the mass effect of all the atoms that leads to decoherence within a few femtosecond.
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Affiliation(s)
- Christophe Narth
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
- Laboratoire de Chimie Théorique, CNRS UMR 7616, Université Pierre et Marie Curie, case courrier 137, 4, Place Jussieu, 75 252 Paris Cedex 05, France
| | - Natacha Gillet
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
| | - Bernard Lévy
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
| | - Isabelle Demachy
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
| | - Aurélien de la Lande
- Laboratoire de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment 349 - Campus d’Orsay, 15, avenue Jean Perrin, 91 405 Orsay Cedex, France
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Anna JM, Baiz CR, Ross MR, McCanne R, Kubarych KJ. Ultrafast equilibrium and non-equilibrium chemical reaction dynamics probed with multidimensional infrared spectroscopy. INT REV PHYS CHEM 2012. [DOI: 10.1080/0144235x.2012.716610] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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25
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Franco I, Brumer P. Electronic coherence dynamics in trans-polyacetylene oligomers. J Chem Phys 2012; 136:144501. [PMID: 22502527 DOI: 10.1063/1.3700445] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ignacio Franco
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA.
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26
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Pachón LA, Brumer P. Computational methodologies and physical insights into electronic energy transfer in photosynthetic light-harvesting complexes. Phys Chem Chem Phys 2012; 14:10094-108. [DOI: 10.1039/c2cp40815e] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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27
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Si YB, Zhong XX, Zhang WW, Zhao Y. Theoretical Investigation on Triplet Excitation Energy Transfer in Fluorene Dimer. CHINESE J CHEM PHYS 2011. [DOI: 10.1088/1674-0068/24/05/538-546] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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28
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Borrelli R, Peluso A. The temperature dependence of radiationless transition rates from ab initio computations. Phys Chem Chem Phys 2011; 13:4420-6. [DOI: 10.1039/c0cp02307h] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Zhang W, Liang W, Zhao Y. Non-Condon effect on charge transport in dithiophene-tetrathiafulvalene crystal. J Chem Phys 2010; 133:024501. [DOI: 10.1063/1.3456545] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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30
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Collini E, Wong CY, Wilk KE, Curmi PMG, Brumer P, Scholes GD. Coherently wired light-harvesting in photosynthetic marine algae at ambient temperature. Nature 2010; 463:644-7. [PMID: 20130647 DOI: 10.1038/nature08811] [Citation(s) in RCA: 827] [Impact Index Per Article: 59.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 12/17/2009] [Indexed: 11/09/2022]
Abstract
Photosynthesis makes use of sunlight to convert carbon dioxide into useful biomass and is vital for life on Earth. Crucial components for the photosynthetic process are antenna proteins, which absorb light and transmit the resultant excitation energy between molecules to a reaction centre. The efficiency of these electronic energy transfers has inspired much work on antenna proteins isolated from photosynthetic organisms to uncover the basic mechanisms at play. Intriguingly, recent work has documented that light-absorbing molecules in some photosynthetic proteins capture and transfer energy according to quantum-mechanical probability laws instead of classical laws at temperatures up to 180 K. This contrasts with the long-held view that long-range quantum coherence between molecules cannot be sustained in complex biological systems, even at low temperatures. Here we present two-dimensional photon echo spectroscopy measurements on two evolutionarily related light-harvesting proteins isolated from marine cryptophyte algae, which reveal exceptionally long-lasting excitation oscillations with distinct correlations and anti-correlations even at ambient temperature. These observations provide compelling evidence for quantum-coherent sharing of electronic excitation across the 5-nm-wide proteins under biologically relevant conditions, suggesting that distant molecules within the photosynthetic proteins are 'wired' together by quantum coherence for more efficient light-harvesting in cryptophyte marine algae.
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Affiliation(s)
- Elisabetta Collini
- Department of Chemistry, Institute for Optical Sciences and Centre for Quantum Information and Quantum Control, University of Toronto, 80 St George Street, Toronto, Ontario, M5S 3H6 Canada
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31
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Theoretical studies of vibrationally resolved absorption and emission spectra: From a single chromophore to multichromophoric oligomers/aggregates. Sci China Chem 2010. [DOI: 10.1007/s11426-010-0075-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Wand A, Kallush S, Shoshanim O, Bismuth O, Kosloff R, Ruhman S. Chirp effects on impulsive vibrational spectroscopy: a multimode perspective. Phys Chem Chem Phys 2010; 12:2149-63. [DOI: 10.1039/b920356g] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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Jones GA, Acocella A, Zerbetto F. On-the-Fly, Electric-Field-Driven, Coupled Electron−Nuclear Dynamics. J Phys Chem A 2008; 112:9650-6. [DOI: 10.1021/jp805360v] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Garth A. Jones
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, United Kingdom, and Dipartimento di Chimica “G. Ciamician”, Università di Bologna, V. F. Selmi 2, 40126, Bologna, Italy
| | - Angela Acocella
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, United Kingdom, and Dipartimento di Chimica “G. Ciamician”, Università di Bologna, V. F. Selmi 2, 40126, Bologna, Italy
| | - Francesco Zerbetto
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, United Kingdom, and Dipartimento di Chimica “G. Ciamician”, Università di Bologna, V. F. Selmi 2, 40126, Bologna, Italy
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34
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Franco I, Shapiro M, Brumer P. Femtosecond dynamics and laser control of charge transport in trans-polyacetylene. J Chem Phys 2008; 128:244905. [PMID: 18601381 DOI: 10.1063/1.2940789] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The induction of dc electronic transport in rigid and flexible trans-polyacetylene oligomers according to the omega versus 2omega coherent control scenario is investigated using a quantum-classical mean field approximation. The approach involves running a large ensemble of mixed quantum-classical trajectories under the influence of omega+2omega laser fields and choosing the initial conditions by sampling the ground-state Wigner distribution function for the nuclei. The vibronic couplings are shown to change the mean single-particle spectrum, introduce ultrafast decoherence, and enhance intramolecular vibrational and electronic relaxation. Nevertheless, even in the presence of significant couplings, limited coherent control of the electronic dynamics is still viable, the most promising route involving the use of femtosecond pulses with a duration that is comparable to the electronic dephasing time. The simulations offer a realistic description of the behavior of a simple coherent control scenario in a complex system and provide a detailed account of the femtosecond photoinduced vibronic dynamics of a conjugated polymer.
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Affiliation(s)
- Ignacio Franco
- Chemical Physics Theory Group, Department of Chemistry and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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35
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Zhang W, Zhu W, Liang W, Zhao Y, Nelsen SF. Ab initio calculations on the intramolecular electron transfer rates of a bis(hydrazine) radical cation. J Phys Chem B 2008; 112:11079-86. [PMID: 18683973 DOI: 10.1021/jp8036507] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Electron transfer (ET) rates of a charge localized (Class II) intervalence radical cation of a bis(hydrazine) are investigated theoretically. First, the intramolecular ET parameters, i.e., reorganization energy, electronic coupling, and effective frequency, are calculated using several ab initio approaches. And then, the extended Sumi-Marcus theory is employed to predict ET rates by using the parameters obtained. The results reveal that the rates of three isomers of [22/hex/22]+, oo+[22/hex/22]+, io +[22/hex/22]+, and oi+[22/hex/22]+, are agreement with the experiment quite well while the rate of isomer ii+[22/hex/22]+ is about 1000 times larger than those of the others. The validity of different ab initio approaches for this system is discussed.
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Affiliation(s)
- Weiwei Zhang
- Department of Chemical Physics, University of Science and Technology of China, Hefei, 230026, P R China
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36
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Franco I, Shapiro M, Brumer P. Robust ultrafast currents in molecular wires through Stark shifts. PHYSICAL REVIEW LETTERS 2007; 99:126802. [PMID: 17930537 DOI: 10.1103/physrevlett.99.126802] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Indexed: 05/25/2023]
Abstract
A novel way to induce ultrafast currents in molecular wires using two incident laser frequencies, omega and 2omega, is demonstrated. The mechanism relies on Stark shifts, instead of near-resonance photon absorption, to transfer population to the excited states and exploits the temporal profile of the field to generate phase-controllable transport. Calculations in a trans- polyacetylene oligomer coupled to metallic leads indicate that the mechanism is highly efficient and robust to ultrafast electronic dephasing processes induced by vibronic couplings.
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Affiliation(s)
- Ignacio Franco
- Chemical Physics Theory Group, Department of Chemistry, Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario, Canada
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37
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Gao F, Zhao Y, Liang W. Theoretical studies toward understanding the excited state dynamics of a bichromophoric molecule. J Chem Phys 2007; 126:224509. [PMID: 17581065 DOI: 10.1063/1.2741559] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
By means of the time-dependent density functional theory, the authors study the torsional dynamics of the lowest singlet electronic excited state (S1) of a bichromophoric molecule, 2-(9-anthryl)-1H-imidazo [4,5-f]-phenanthroline (AIP). The intramolecular dynamical relaxation process, the S1 potential energy surface, and the vibrationally resolved electronic absorption and fluorescence spectra are estimated. The results reveal that the strong electron-nuclear coupling leads to a dynamic structural distortion in S1 state so that the mirror-image symmetry of absorption and fluorescence spectra of AIP breaks down. The torsional motion between the donor and acceptor moieties in AIP favors the intramolecular electronic energy transfer process. The transfer rate is dominated by the relaxation time along S1 low-frequency torsional motion.
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Affiliation(s)
- Fang Gao
- Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026, People's Republic of China
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38
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Niewodniczański W, Bartkowiak W. Theoretical study of geometrical and nonlinear optical properties of pyridinum N-phenolate betaine dyes. J Mol Model 2007; 13:793-800. [PMID: 17447089 DOI: 10.1007/s00894-007-0198-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Accepted: 03/05/2007] [Indexed: 11/28/2022]
Abstract
This paper presents an ab initio quantum chemical investigation of the geometrical structures and the non-linear optical properties (NLO) of three structural isomers of pyridinium N-phenolate betaine dye. The ground state geometrical parameters and the first-order hyperpolarizabilities were calculated using the Hartree-Fock (HF) as well as the second-order perturbation Møller-Pleset (MP2) method with the 6-31G, 6-31G(d), 6-31G(d,p), 6-31+G(d), 6-31++G(d,p), 6-311+G(d), aug-cc-PVDZ and the recently developed Z3PolX basis sets. Moreover, the first-order hyperpolarizability was calculated at the coupled cluster singles and doubles (CCSD/6-31+G(d)) level of theory. The analysis of the results of calculations for the investigated isomers indicates that there are important differences in their NLO activities. Additionally, it was shown that Z3PolX basis set works reasonable well for betaine dyes.
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Affiliation(s)
- Wawrzyniec Niewodniczański
- Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology, Wybrzeze Wyspiańskiego 27, Wrocław, Poland.
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39
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Peng F, Shen Z. Electronic and steric effects of methyl substituent in Samarium (III) phenolates on their initiation activities in polymerization of ε-caprolactone. J Appl Polym Sci 2007. [DOI: 10.1002/app.26842] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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40
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Kim H, Hwang H, Rossky PJ. Quantum Simulation of Solution Phase Intramolecular Electron Transfer Rates in Betaine-30. J Phys Chem A 2006; 110:11223-9. [PMID: 17004730 DOI: 10.1021/jp063222d] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mixed quantum-classical atomistic simulations have been carried out to investigate the mechanistic details of excited state intramolecular electron transfer in a betaine-30 molecule in acetonitrile. The key electronic degrees of freedom of the solute molecule are treated quantum mechanically using the semiempirical Pariser-Parr-Pople Hamiltonian, including the solvent influence on electronic structure. The intramolecular vibrational modes are also treated explicitly at a quantum level, with the remaining elements treated classically using empirical potentials. The electron-transfer rate, corresponding to S1 --> S0 relaxation, is evaluated via time-dependent perturbation theory with the explicit inclusion of the dynamics of solvation and intramolecular conformation. The calculations reveal that, while solvation dynamics is critical to the rate, the intramolecular torsional dynamics also plays an important role. The importance of the use of multiple high-frequency quantum modes is also discussed.
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Affiliation(s)
- Hyojoon Kim
- Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
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41
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Liang W, Zhao Y, Sun J, Song J, Hu S, Yang J. Electronic Excitation of Polyfluorenes: A Theoretical Study. J Phys Chem B 2006; 110:9908-15. [PMID: 16706446 DOI: 10.1021/jp0572481] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present systematic, theoretical investigations on structure-property correlations in polyfluorenes (PFs) derived mainly from the chain morphology, oligomer length, and chemical substitutent. Both the vertical absorptions and the vibrational contributions to electronic absorption and fluorescence spectra have been calculated. The effect of temperature on the nature of photoexcitations of PFs has been demonstrated. It is found that the vibronic (electronic and vibrational) structures of PFs are morphology-dependent. beta-phase oligofluorenes (beta-(FL)(n)) and ladder-type poly(p-phenylene) (LPPP) oligomers show a red shift compared to the spectra of alpha-(FL)(n). The asymmetry of the absorption and fluorescence spectra in alpha-(FL)(n) and the fluorenone (FLO) defect oligofluorenes alpha-(FL)(n)(-)(m)(FLO)(m) is significantly more pronounced than that in planarized beta-(FL)(n) and LPPP oligomers. By properly taking into account the anharmonic torsion potentials resulting from the strong electronic and nuclear coupling in the oligofluorenes, we have reasonably reproduced the experimentally observed spectroscopic features. The low-energy on-chain chemical defect sites such as FLO units act as charge-trapping sites for singlet excitations, are the predominantly lighting-emitting species, and thus alter the blue light-emitting properties of PFs whereas the blue-light-emitting properties of PFs are hardly influenced by the hole-transporting molecules. The optical properties of PFs have been predicted by the finite-size calculations. Energy gaps of PFs are estimated by extrapolations from excitation energies of oligofluorenes up to 21 FL units.
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Affiliation(s)
- Wanzhen Liang
- Hefei National Laboratory for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, People's Republic of China.
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42
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Pugliesi I, Watkins MJ, Müller-Dethlefs K. Franck−Condon Simulations of Clusters: Phenol−Nitrogen. J Phys Chem A 2006; 110:4668-77. [PMID: 16599433 DOI: 10.1021/jp058227+] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Multidimensional Franck-Condon simulations of the resonance enhanced multiphoton ionization (REMPI) and mass-analyzed threshold ionization (MATI) spectra of phenol-nitrogen are obtained from CASSCF, MRCI, and SACCI optimized geometries. In the REMPI simulations, the results are unsatisfactory, as the transitions associated with intermolecular modes are widely underestimated and much less intense than those associated with intramolecular modes. Conversely, the simulations of the MATI spectra show a good similarity to experiment. The best simulations are obtained in both instances from the SACCI optimized geometries. Furthermore, the simulations suggest that the two most prominent Franck-Condon envelopes present in the MATI spectra are due to the sigma and sigma + ngamma' combination bands in accord with the assignments of the MATI spectra of the analogous phenol-carbon monoxide cluster.
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Affiliation(s)
- Igor Pugliesi
- Department of Chemistry, York Centre of Laser Spectroscopy, YCLS, The University of York, Heslington, York YO10 5DD, UK.
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43
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Pugliesi I, Müller-Dethlefs K. The Use of Multidimensional Franck−Condon Simulations to Assess Model Chemistries: A Case Study on Phenol. J Phys Chem A 2006; 110:4657-67. [PMID: 16599432 DOI: 10.1021/jp058226h] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Multidimensional Franck-Condon simulations of the dispersed fluorescence spectra of phenol generated with geometries obtained from the highly correlated post-Hartree-Fock methods CASSCF, MRCI, and SACCI are presented. While the simulations based on CASSCF and MRCI optimized geometries are very similar to each other and fail to reproduce the experimentally measured intensities faithfully, the simulations obtained from SACCI optimized geometries are very close to the experimental spectra. The code developed for the multidimensional Franck-Condon simulations is described. It is shown that the integral storage problem common to the evaluation of multidimensional Franck-Condon integrals can be overcome by saving all quantities needed to disk. This strategy allows the code to run on computers with limited resources and is very well suited for application to molecules with a very large number of vibrational modes.
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Affiliation(s)
- Igor Pugliesi
- Department of Chemistry, York Centre of Laser Spectroscopy, YCLS, The University of York, Heslington, York YO10 5DD, UK.
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Weiss EA, Katz G, Goldsmith RH, Wasielewski MR, Ratner MA, Kosloff R, Nitzan A. Electron transfer mechanism and the locality of the system-bath interaction: A comparison of local, semilocal, and pure dephasing models. J Chem Phys 2006; 124:74501. [PMID: 16497051 DOI: 10.1063/1.2168457] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We simulate the effects of two types of dephasing processes, a nonlocal dephasing of system eigenstates and a dephasing of semilocal eigenstates, on the rate and mechanism of electron transfer (eT) through a series of donor-bridge-acceptor systems, D-B(N)-A, where N is the number of identical bridge units. Our analytical and numerical results show that pure dephasing, defined as the perturbation of system eigenstates through the system-bath interaction, does not disrupt coherent eT because it induces no localization; electron transfer may proceed through superexchange in a system undergoing only pure dephasing. A more physically reasonable description may be obtained via a system-bath interaction that reflects the perturbation of more local electronic structure by local nuclear distortions and dipole interactions. The degree of locality of this interaction is guided by the structure of the system Hamiltonian and by the nature of the measurement performed on the system (i.e., the nature of the environment). We compare our result from this "semilocal" model with an even more local phenomenological dephasing model. We calculate electron transfer rate by obtaining nonequilibrium steady-state solutions for the elements of a reduced density matrix; a semigroup formalism is used to write down the dissipative part of the equation of motion.
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Affiliation(s)
- Emily A Weiss
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA.
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45
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Jasper AW, Truhlar DG. Electronic decoherence time for non-Born-Oppenheimer trajectories. J Chem Phys 2005; 123:64103. [PMID: 16122296 DOI: 10.1063/1.1995695] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An expression is obtained for the electronic decoherence time of the reduced density electronic matrix in mixed quantum-classical molecular-dynamics simulations. The result is obtained by assuming that decoherence is dominated by the time dependence of the overlap of minimum-uncertainty packets and then maximizing the rate with respect to the parameters of the wave packets. The expression for the decay time involves quantities readily available in non-Born-Oppenheimer molecular-dynamics simulations, and it is shown to have a reasonable form when compared with two other formulas for the decay time that have been previously proposed.
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Affiliation(s)
- Ahren W Jasper
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA
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Correlation between phenol structure and catalytic activity of samarium(III) phenolates in polymerization of ɛ-caprolactone. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcata.2004.12.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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