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Gay-Balmaz F, Tronci C. Complex Fluid Models of Mixed Quantum-Classical Dynamics. JOURNAL OF NONLINEAR SCIENCE 2024; 34:81. [PMID: 38966687 PMCID: PMC11219418 DOI: 10.1007/s00332-024-10044-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 05/08/2024] [Indexed: 07/06/2024]
Abstract
Several methods in nonadiabatic molecular dynamics are based on Madelung's hydrodynamic description of nuclear motion, while the electronic component is treated as a finite-dimensional quantum system. In this context, the quantum potential leads to severe computational challenges and one often seeks to neglect its contribution, thereby approximating nuclear motion as classical. The resulting model couples classical hydrodynamics for the nuclei to the quantum motion of the electronic component, leading to the structure of a complex fluid system. This type of mixed quantum-classical fluid models has also appeared in solvation dynamics to describe the coupling between liquid solvents and the quantum solute molecule. While these approaches represent a promising direction, their mathematical structure requires a certain care. In some cases, challenging higher-order gradients make these equations hardly tractable. In other cases, these models are based on phase-space formulations that suffer from well-known consistency issues. Here, we present a new complex fluid system that resolves these difficulties. Unlike common approaches, the current system is obtained by applying the fluid closure at the level of the action principle of the original phase-space model. As a result, the system inherits a Hamiltonian structure and retains energy/momentum balance. After discussing some of its structural properties and dynamical invariants, we illustrate the model in the case of pure-dephasing dynamics. We conclude by presenting some invariant planar models.
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Affiliation(s)
- François Gay-Balmaz
- Division of Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Cesare Tronci
- Department of Mathematics, University of Surrey, Guildford, UK
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2
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Polonius S, Lehrner D, González L, Mai S. Resolving Photoinduced Femtosecond Three-Dimensional Solute-Solvent Dynamics through Surface Hopping Simulations. J Chem Theory Comput 2024; 20:4738-4750. [PMID: 38768386 PMCID: PMC11171268 DOI: 10.1021/acs.jctc.4c00169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/22/2024] [Accepted: 05/07/2024] [Indexed: 05/22/2024]
Abstract
Photoinduced dynamics in solution is governed by mutual solute-solvent interactions, which give rise to phenomena like solvatochromism, the Stokes shift, dual fluorescence, or charge transfer. Understanding these phenomena requires simulating the solute's photoinduced dynamics and simultaneously resolving the three-dimensional solvent distribution dynamics. If using trajectory surface hopping (TSH) to this aim, thousands of trajectories are required to adequately sample the time-dependent three-dimensional solvent distribution functions, and thus resolve the solvent dynamics with sub-Ångstrom and femtosecond accuracy and sufficiently low noise levels. Unfortunately, simulating thousands of trajectories with TSH in the framework of hybrid quantum mechanical/molecular mechanical (QM/MM) can be prohibitively expensive when employing ab initio electronic structure methods. To tackle this challenge, we recently introduced a computationally efficient approach that combines efficient linear vibronic coupling models with molecular mechanics (LVC/MM) via electrostatic embedding [Polonius et al., JCTC 2023, 19, 7171-7186]. This method provides solvent-embedded, nonadiabatically coupled potential energy surfaces while scaling similarly to MM force fields. Here, we employ TSH with LVC/MM to unravel the photoinduced dynamics of two small thiocarbonyl compounds solvated in water. We describe how to estimate the number of trajectories required to produce nearly noise-free three-dimensional solvent distribution functions and present an analysis based on approximately 10,000 trajectories propagated for 3 ps. In the electronic ground state, both molecules exhibit in-plane hydrogen bonds to the sulfur atom. Shortly after excitation, these bonds are broken and reform perpendicular to the molecular plane on timescales that differ by an order of magnitude due to steric effects. We also show that the solvent relaxation dynamics is coupled to the electronic dynamics, including intersystem crossing. These findings are relevant to advance the understanding of the coupled solute-solvent dynamics of solvated photoexcited molecules, e.g., biologically relevant thio-nucleobases.
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Affiliation(s)
- Severin Polonius
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
- Vienna
Doctoral School in Chemistry (DoSChem), University of Vienna, Währinger Str. 42, 1090 Vienna, Austria
| | - David Lehrner
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
| | - Leticia González
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
- Vienna
Research Platform on Accelerating Photoreaction Discovery, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria
| | - Sebastian Mai
- Institute
of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 17, 1090 Vienna, Austria
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3
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Ould Mohamed L, Abtouche S, Ghoualem Z, Assfeld X. Unraveling redox pathways of the disulfide bond in dimethyl disulfide: Ab initio modeling. J Mol Model 2024; 30:180. [PMID: 38780881 DOI: 10.1007/s00894-024-05963-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 05/03/2024] [Indexed: 05/25/2024]
Abstract
CONTEXT In cellular environments, the reduction of disulfide bonds is pivotal for protein folding and synthesis. However, the intricate enzymatic mechanisms governing this process remain poorly understood. This study addresses this gap by investigating a disulfide bridge reduction reaction, serving as a model for comprehending electron and proton transfer in biological systems. Six potential mechanisms for reducing the dimethyl disulfide (DMDS) bridge through electron and proton capture were explored. Thermodynamic and kinetic analyses elucidated the sequence of proton and electron addition. MD-PMM, a method that combines molecular dynamics simulations and quantum-chemical calculations, was employed to compute the redox potential of the mechanism. This research provides valuable insights into the mechanisms and redox potentials involved in disulfide bridge reduction within proteins, offering an understanding of phenomena that are challenging to explore experimentally. METHODS All calculations used the Gaussian 09 software package at the MP2/6-311 + g(d,p) theory level. Visualization of the molecular orbitals and electron densities was conducted using Gaussview6. Molecular dynamics simulations were performed using GROMACS with the CHARMM36 force field. The PyMM program (Python Program for QM/MM Simulations Based on the Perturbed Matrix Method) is used to apply the Perturbed Matrix Method to MD simulations.
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Affiliation(s)
- Lina Ould Mohamed
- Laboratoire de Physico Chimie Théorique Et Chimie Informatique, LPCTCI, Faculté de Chimie, USTHB, 16111, Algiers, Algeria
| | - Soraya Abtouche
- Laboratoire de Physico Chimie Théorique Et Chimie Informatique, LPCTCI, Faculté de Chimie, USTHB, 16111, Algiers, Algeria.
| | - Zeyneb Ghoualem
- Laboratoire de Physico Chimie Théorique Et Chimie Informatique, LPCTCI, Faculté de Chimie, USTHB, 16111, Algiers, Algeria
| | - Xavier Assfeld
- Physique et Chimie Théoriques, UMR 7019, Faculté des Sciences et Technologies, Université de Lorraine, BP 70239, 54506, Vandoeuvre Lès Nancy Cedex, France
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4
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Lamas I, Montero R, Martínez-Martínez V, Longarte A. Photodynamics of azaindoles in polar media: the influence of the environment. Phys Chem Chem Phys 2024; 26:3240-3252. [PMID: 38193884 DOI: 10.1039/d3cp03412g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
We have studied the relaxation dynamics of a family of azaindole (AI) structural isomers, 4-, 5-, 6- and 7-AI, by steady-state and time-resolved methods (fs-transient absorption and fluorescence up-conversion), in solvents of different polarity. The measurements in aprotic solvents show distinctive fluorescence yields and excited state lifetimes among the isomers, which are tuned by the polarity of the medium. Guided by simple TD-DFT calculations and based on the behavior observed in the isolated species, it has been possible to address the influence of the environment polarity on the relaxation route. According to the obtained picture, the energy of the nπ* state, which is strongly dependent on the position of the pyridinic nitrogen, controls the rate of the internal conversion channel that accounts for the distinctive photophysical behavior of the isomers. On the other hand, preliminary measurements in protic media (methanol) show a very different photodynamical behavior, in which the anomalous measured fluorescent patterns are very likely the result of reactive channels (proton transfer) triggered by the electronic excitation.
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Affiliation(s)
- Iker Lamas
- Departamento de Química-Física Facultad de Ciencia y Tecnología. Universidad del País Vasco (UPV/EHU) Apart. 644, 48080 Bilbao, Spain.
| | - Raúl Montero
- SGIKER Laser Facility Facultad de Ciencia y Tecnología. Universidad del País Vasco (UPV/EHU) 48940, Leioa, Spain.
| | - Virginia Martínez-Martínez
- Departamento de Química-Física Facultad de Ciencia y Tecnología. Universidad del País Vasco (UPV/EHU) Apart. 644, 48080 Bilbao, Spain.
| | - Asier Longarte
- Departamento de Química-Física Facultad de Ciencia y Tecnología. Universidad del País Vasco (UPV/EHU) Apart. 644, 48080 Bilbao, Spain.
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5
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Xiao T, Song X. A Gaussian field approach to the solvation of spherical ions in electrolyte solutions. J Chem Phys 2024; 160:034102. [PMID: 38226821 DOI: 10.1063/5.0187141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 12/25/2023] [Indexed: 01/17/2024] Open
Abstract
In this work, the electrostatic response of an electrolyte solution to a spherical ion is studied with a Gaussian field theory. In order to capture the ionic correlation effect in concentrated solutions, the bulk dielectric response function is described by a two-Yukawa response function. The modified response function of the solution is solved analytically in the spherical geometry, from which the induced charge density and the electrostatic energy are also derived analytically. Comparisons with results for small ions in electrolyte solutions from the hyper-netted chain theory demonstrate the validity of the Gaussian field theory.
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Affiliation(s)
- Tiejun Xiao
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University, Guiyang People's Republic of China
| | - Xueyu Song
- Department of Chemistry and Ames Laboratory, Iowa State University, Ames, Iowa 50011, USA
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Tsuji M, Abuhadba S, Chen A, Ito M, Makhijani A, Kuwahara Y, Esipova T, Mani T. Red-Colored Circularly Polarized Luminescence from a Benzo-Fused BODIPY-BINOL Complex. J Phys Chem B 2023; 127:9781-9787. [PMID: 37915207 DOI: 10.1021/acs.jpcb.3c05496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Red emission with sharp bandwidth and high quantum yield is a desired characteristic for organic chromophores in optoelectronic, spintronic, and biomedical applications. Here, we observe circularly polarized luminescence (CPL) with these characteristics from a benzo-fused BODIPY-BINOL complex (1). Using time-resolved optical spectroscopy, electrochemistry, and density functional theory calculations, we showed that the emissive excited state of 1 does not have a charge-transfer (CT) character, unlike that of the regular BODIPY counterpart (2). The rigidity and the lack of CT character make this class of molecules an appealing platform for CPL-active molecules in the red spectral region, with ample room for improvement in the dissymmetry factor and brightness.
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Affiliation(s)
- Miu Tsuji
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Sara Abuhadba
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, Illinois 60660, United States
| | - Angela Chen
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Mio Ito
- Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Amrita Makhijani
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Yutaka Kuwahara
- Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
- International Research Organization for Advanced Science and Technology (IROAST), Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan
| | - Tatiana Esipova
- Department of Chemistry and Biochemistry, Loyola University Chicago, Chicago, Illinois 60660, United States
| | - Tomoyasu Mani
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973, United States
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7
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Guo Y, Feng M, Kuang Z, Abeywickrama CS, Pang Y, Xia A. Unveiling Solvation Dynamics of Excited and Ground States via Ultrafast Pump-Dump-Probe Spectroscopy. J Phys Chem B 2023; 127:7764-7771. [PMID: 37656037 DOI: 10.1021/acs.jpcb.3c05450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The conventional ultrafast pump-probe spectroscopy has primarily focused on examining the formation and decay of the excited state intermediates, but it is very difficult to detect those intermediates while the formation is slow and dissipation is much fast because of the limited concentration during the intrinsic photocycle. To address this issue, a multipulse ultrafast pump-dump-probe spectroscopy was employed to generate and probe the short-lived ground state intermediates (GSIs) in an electronic push-pull pyrene derivative (EPP). This particular derivative undergoes planarized intramolecular charge transfer (PICT) in the excited state upon initial femtosecond pulse excitation. After applying the dump pulse once the PICT was formed, the blue-shifted transient absorption GSIs with the ground state dynamics of the structure recovery was directly observed. It is found that GSIs undergo slower reorganization than the PICT formation in the excited state of EPP due to the solvation effect with different dipole moments of ground states and excited states. These findings provide a comprehensive understanding of the full photocycle dynamics of both the ground and excited states, shedding light on the presence of hidden ground state behaviors.
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Affiliation(s)
- Yuanyuan Guo
- School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, People's Republic of China
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Minjun Feng
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Zhuoran Kuang
- School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, People's Republic of China
| | | | - Yi Pang
- Department of Chemistry, University of Akron, Akron, Ohio 44325, United States
| | - Andong Xia
- School of Science, Beijing University of Posts and Telecommunications (BUPT), Beijing 100876, People's Republic of China
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8
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Xiao T, Song X. A Gaussian field approach to the planar electric double layer structures in electrolyte solutions. J Chem Phys 2023; 158:2887562. [PMID: 37125713 DOI: 10.1063/5.0138568] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 04/17/2023] [Indexed: 05/02/2023] Open
Abstract
In this work, the planar, electric, double-layer structures of non-polarizable electrodes in electrolyte solutions are studied with Gaussian field theory. A response function with two Yukawa functions is used to capture the electrostatic response of the electrolyte solution, from which the modified response function in the planar symmetry is derived analytically. The modified response function is further used to evaluate the induced charge density and the electrostatic potential near an electrode. The Gaussian field theory, combined with a two-Yukawa response function, can reproduce the oscillatory decay behavior of the electric potentials in concentrated electrolyte solutions. When the exact sum rules for the bulk electrolyte solutions and the electric double layers are used as constraints to determine the parameters of the response function, the Gaussian field theory could at least partly capture the nonlinear response effect of the surface charge density. Comparison with results for a planar electrode with fixed surface charge densities from molecular simulations demonstrates the validity of Gaussian field theory.
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Affiliation(s)
- Tiejun Xiao
- Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Guizhou Synergetic Innovation Center of Scientific Big Data for Advanced Manufacturing Technology, Guizhou Education University, Guiyang 550018, People's Republic of China
| | - Xueyu Song
- Ames Laboratory and Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
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9
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Si WD, Zhang C, Zhou M, Tian WD, Wang Z, Hu Q, Song KP, Feng L, Huang XQ, Gao ZY, Tung CH, Sun D. Two triplet emitting states in one emitter: Near-infrared dual-phosphorescent Au 20 nanocluster. SCIENCE ADVANCES 2023; 9:eadg3587. [PMID: 36989358 PMCID: PMC10058230 DOI: 10.1126/sciadv.adg3587] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 03/01/2023] [Indexed: 06/19/2023]
Abstract
Intrinsic dual-emission (DE) of gold nanoclusters in the near-infrared (NIR) are fascinating for fundamental importance and practical applications, but their synthesis remains a formidable challenge and sophisticated excited-state processes make elucidating DE mechanisms much more arduous. Here, we report an all-alkynyl-protected gold nanocluster, Au20, showing a prolate Au12 tri-octahedral kernel surrounded by two Au2(CZ-PrA)3 dimers, four Au(CZ-PrA)2 monomers, and two CZ-PrA- bridges. Au20 exhibits distinguished photophysical properties including NIR DE at 820 and 940 nm, microsecond radiative relaxation, and 6.26% photoluminescent quantum yield at ambient environment in nondegassed solution. Combining systematic studies on steady/transient spectroscopy and theoretical calculation, we identified two triplet charge transfer (CT) states, ligand-to-kernel and kernel-based CT states as DE origins. Furthermore, this NIR DE exhibits highly independent and sensitive response to surrounding environments, which well coincide with its mechanism. This work not only provides a substantial structure model to understand a distinctive DE mechanism but also motivates the further development of NIR DE materials.
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Affiliation(s)
- Wei-Dan Si
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China
| | - Chengkai Zhang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China
| | - Meng Zhou
- Hefei National Research Center for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Wei-Dong Tian
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China
| | - Zhi Wang
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China
| | - Qingsong Hu
- Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Hubei University of Arts and Science, Xiangyang 441053, China
| | - Ke-Peng Song
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China
| | - Lei Feng
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China
| | - Xian-Qiang Huang
- Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, and School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252000, People’s Republic of China
| | - Zhi-Yong Gao
- School of Chemistry and Chemical Engineering, Henan Normal University, Henan, Xinxiang 453007, People’s Republic of China
| | - Chen-Ho Tung
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China
| | - Di Sun
- School of Chemistry and Chemical Engineering, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, People’s Republic of China
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10
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Semiclassical Theory of Multistage Nonequilibrium Electron Transfer in Macromolecular Compounds in Polar Media with Several Relaxation Timescales. Int J Mol Sci 2022; 23:ijms232415793. [PMID: 36555434 PMCID: PMC9779366 DOI: 10.3390/ijms232415793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 12/14/2022] Open
Abstract
Many specific features of ultrafast electron transfer (ET) reactions in macromolecular compounds can be attributed to nonequilibrium configurations of intramolecular vibrational degrees of freedom and the environment. In photoinduced ET, nonequilibrium nuclear configurations are often produced at the stage of optical excitation, but they can also be the result of electron tunneling itself, i.e., fast redistribution of charges within the macromolecule. A consistent theoretical description of ultrafast ET requires an explicit consideration of the nuclear subsystem, including its evolution between electron jumps. In this paper, the effect of the multi-timescale nuclear reorganization on ET transitions in macromolecular compounds is studied, and a general theory of ultrafast ET in non-Debye polar environments with a multi-component relaxation function is developed. Particular attention is paid to designing the multidimensional space of nonequilibrium nuclear configurations, as well as constructing the diabatic free energy surfaces for the ET states. The reorganization energies of individual ET transitions, the equilibrium energies of ET states, and the relaxation properties of the environment are used as input data for the theory. The effect of the system-environment interaction on the ET kinetics is discussed, and mechanisms for enhancing the efficiency of charge separation in macromolecular compounds are analyzed.
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11
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Blockade of persistent colored isomer formation in photochromic 3H-naphthopyrans by excited-state intramolecular proton transfer. Sci Rep 2022; 12:19159. [DOI: 10.1038/s41598-022-23759-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 11/04/2022] [Indexed: 11/11/2022] Open
Abstract
AbstractIn photochemistry the excited-state intramolecular proton transfer process (ESIPT) is often observed as a highly efficient singlet excited state depletion pathway, which in the presence of a strong intramolecular hydrogen bond may proceed on a subpicosecond time scale. The present work describes the suppression of unwanted transoid-trans isomer formation in photochromic 3H-naphthopyran derivatives by the introduction of a 5-hydroxy substituent. According to time-resolved spectroscopy experiments and excited-state ab initio calculations, transoid-cis → transoid-trans photoisomerization is reduced by a competitive ESIPT channel in nonpolar solvent (cyclohexane). Upon specific solute–solvent interactions (methanol, acetonitrile) the intramolecular hydrogen bond in the transoid-cis form is perturbed, favoring the internal conversion S1 → S0 process as photostabilizing channel.
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12
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Kushida S, Wang K, Genet C, Ebbesen TW. Ultrafast Dynamics of Solute Molecules Probed by Resonant Optical Kerr Effect Spectroscopy. J Phys Chem Lett 2022; 13:9309-9315. [PMID: 36178160 DOI: 10.1021/acs.jpclett.2c02461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Ultrafast molecular dynamics in fluids is of great importance in many biological and chemical systems. Although such dynamics in bulk liquids has been explored by various methods, experimental tools that unveil the dynamics of solvated solutes are limited. In this work, we have developed resonant optical Kerr effect spectroscopy (ROKE), which is an analogue of optical Kerr effect spectroscopy that measures the reorientational relaxation of a dilute solute in solution. By adjusting the pump and probe wavelengths at the resonant absorption band of a solute, the time response of the solute was distinguished easily from the negligible signal of the solvent. The heterodyne detection of ROKE enables the determination of reorientational relaxation time constants with an accuracy of 2.6%. The signal-to-noise ratio was high enough (average ∼26.7) to obtain an adequate signal from even a 10 μM solution. Thus, ROKE is a powerful tool to study solute dynamics with high sensitivity in a broad range of applications.
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Affiliation(s)
- Soh Kushida
- University of Strasbourg, CNRS, ISIS & icFRC, 8 allée Gaspard Monge, 67000Strasbourg, France
- Faculty of Pure and Applied Sciences, and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba305-8577, Japan
| | - Kuidong Wang
- University of Strasbourg, CNRS, ISIS & icFRC, 8 allée Gaspard Monge, 67000Strasbourg, France
| | - Cyriaque Genet
- University of Strasbourg, CNRS, ISIS & icFRC, 8 allée Gaspard Monge, 67000Strasbourg, France
| | - Thomas W Ebbesen
- University of Strasbourg, CNRS, ISIS & icFRC, 8 allée Gaspard Monge, 67000Strasbourg, France
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13
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Pinto CM, Pina J, Delgado-Pinar E, Seixas de Melo JS. Excited state deactivation mechanisms in Shikonin rationalized from its naphthoquinone parent structures. Phys Chem Chem Phys 2022; 24:20348-20356. [PMID: 35980224 DOI: 10.1039/d2cp01829b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Shikonin, a naphthoquinone dye, is a molecule of colour of natural origin, whose peculiar properties have not yet been fully rationalized. Its core structure consists of a di-hydroxy-naphthoquinone with an additional non-aromatic hydroxy group. From a comprehensive study involving fast spectroscopic techniques (fs-TA and fs-UC) and TDDFT electronic structure calculations on shikonin (Shk) and its derivatives 5-hydroxy-1,4-naphthoquinone (5HNQ), 5,8-diacetoxy-1,4-naphthoquinone (DiAc), 5,8-dihidroxy-1,4-naphthoquinone (DHNQ) and acetylshikonin, AcShk, it is shown that intramolecular excited state proton transfer (ESIPT) is present and is determinant in the deactivation of the hydroxy containing molecules. This is mirrored by the dominance of the internal conversion deactivation channel. In Shk, the non-aromatic hydroxy group determines the preferred conformer in both the ground- and excited-state, as reflected in the doubling of the fluorescence quantum yield value of this molecule relative to DHNQ. From fs-UC, a kinetic isotopic effect of 1.7 was obtained for DHNQ.
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Affiliation(s)
- Catarina M Pinto
- Department of Chemistry, University of Coimbra, CQC-IMS, Rua Larga, 3004-535 Coimbra, Portugal.
| | - João Pina
- Department of Chemistry, University of Coimbra, CQC-IMS, Rua Larga, 3004-535 Coimbra, Portugal.
| | - Estefanía Delgado-Pinar
- Department of Chemistry, University of Coimbra, CQC-IMS, Rua Larga, 3004-535 Coimbra, Portugal.
| | - J Sérgio Seixas de Melo
- Department of Chemistry, University of Coimbra, CQC-IMS, Rua Larga, 3004-535 Coimbra, Portugal.
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14
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Jin C, Qi D, Yao J, He Y, Ding P, Guo Z, Huang Z, He Y, Yao Y, Wang Z, Sun Z, Zhang S. Weighted multi-scale denoising via adaptive multi-channel fusion for compressed ultrafast photography. OPTICS EXPRESS 2022; 30:31157-31170. [PMID: 36242204 DOI: 10.1364/oe.469345] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 07/25/2022] [Indexed: 06/16/2023]
Abstract
Being capable of passively capturing transient scenes occurring in picoseconds and even shorter time with an extremely large sequence depth in a snapshot, compressed ultrafast photography (CUP) has aroused tremendous attention in ultrafast optical imaging. However, the high compression ratio induced by large sequence depth brings the problem of low image quality in image reconstruction, preventing CUP from observing transient scenes with fine spatial information. To overcome these restrictions, we propose an efficient image reconstruction algorithm with multi-scale (MS) weighted denoising based on the plug-and-play (PnP) based alternating direction method of multipliers (ADMM) framework for multi-channel coupled CUP (MC-CUP), named the MCMS-PnP algorithm. By removing non-Gaussian distributed noise using weighted MS denoising during each iteration of the ADMM, and adaptively adjusting the weights via sufficiently exploiting the coupling information among different acquisition channels collected by MC-CUP, a synergistic combination of hardware and algorithm can be realized to significantly improve the quality of image reconstruction. Both simulation and experimental results demonstrate that the proposed adaptive MCMS-PnP algorithm can effectively improve the accuracy and quality of reconstructed images in MC-CUP, and extend the detectable range of CUP to transient scenes with fine structures.
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15
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Ramamurthy V, Sen P, Elles CG. Ultrafast Excited State Dynamics of Spatially Confined Organic Molecules. J Phys Chem A 2022; 126:4681-4699. [PMID: 35786917 DOI: 10.1021/acs.jpca.2c03276] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This Feature Article highlights the role of spatial confinement in controlling the fundamental behavior of molecules. Select examples illustrate the value of using space as a tool to control and understand excited-state dynamics through a combination of ultrafast spectroscopy and conventional steady-state methods. Molecules of interest were confined within a closed molecular capsule, derived from a cavitand known as octa acid (OA), whose internal void space is sufficient to accommodate molecules as long as tetracene and as wide as pyrene. The free space, i.e., the space that is left following the occupation of the guest within the host, is shown to play a significant role in altering the behavior of guest molecules in the excited state. The results reported here suggest that in addition to weak interactions that are commonly emphasized in supramolecular chemistry, the extent of empty space (i.e., the remaining void space within the capsule) is important in controlling the excited-state behavior of confined molecules on ultrafast time scales. For example, the role of free space in controlling the excited-state dynamics of guest molecules is highlighted by probing the cis-trans isomerization of stilbenes and azobenzenes within the OA capsule. Isomerization of both types of molecule are slowed when they are confined within a small space, with encapsulated azobenzenes taking a different reaction pathway compared to that in solution upon excitation to S2. In addition to steric constraints, confinement of reactive molecules in a small space helps to override the need for diffusion to bring the reactants together, thus enabling the measurement of processes that occur faster than the time scale for diffusion. The advantages of reducing free space and confining reactive molecules are illustrated by recording unprecedented excimer emission from anthracene and by measuring ultrafast electron transfer rates across the organic molecular wall. By monitoring the translational motion of anthracene pairs in a restricted space, it has been possible to document the pathway undertaken by excited anthracene from inception to the formation of the excimer on the excited-state surface. Similarly, ultrafast electron transfer experiments pursued here have established that the process is not hindered by a molecular wall. Apparently, the electron can cross the OA capsule wall provided the donor and acceptor are in close proximity. Measurements on the ultrafast time scale provide crucial insights for each of the examples presented here, emphasizing the value of both "space" and "time" in controlling and understanding the dynamics of excited molecules.
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Affiliation(s)
| | - Pratik Sen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, UP 208 016, India
| | - Christopher G Elles
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
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16
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Hou Z, Guan J, Peng J, Li X, Yu Z, Zheng J. Double crossing conical intersections and anti-Vavilov fluorescence in tetraphenyl ethylene. J Chem Phys 2022; 156:144302. [DOI: 10.1063/5.0082679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Conical intersections (CIs) provide effective fast nonradiative decay pathways for electronic excitation, which can significantly influence molecular photoluminescence properties. However, in many cases, crossing a CI does not have direct observables, making studies of CIs experimentally challenging. Herein, the theoretically predicted double CIs by cis–trans twisting and cyclization in tetraphenyl ethylene, a well-known aggregation-induced emission molecule, are investigated with excitation dependent ultrafast UV/IR spectroscopy and fluorescence. Both the fluorescence quantum yield and the efficiency of cyclization are found to be smaller with a shorter excitation wavelength. An abrupt change occurs at about 300–310 nm. The results imply that crossing the twisting CI has a larger barrier than the cyclization CI, and the cis–trans twisting motion is probably involved with large solvation reorganization.
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Affiliation(s)
- Zhuowei Hou
- College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Jianxin Guan
- College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Jie Peng
- College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Xinmao Li
- College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Zhihao Yu
- College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, People’s Republic of China
| | - Junrong Zheng
- College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, People’s Republic of China
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17
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Madea D, Mujawar T, Dvořák A, Pospíšilová K, Muchová L, Čubáková P, Kloz M, Švenda J, Vítek L, Klán P. Photochemistry of ( Z)-Isovinylneoxanthobilirubic Acid Methyl Ester, a Bilirubin Dipyrrinone Subunit: Femtosecond Transient Absorption and Stimulated Raman Emission Spectroscopy. J Org Chem 2022; 87:3089-3103. [PMID: 35130431 DOI: 10.1021/acs.joc.1c02870] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bilirubin (BR) is an essential metabolite formed by the catabolism of heme. Phototherapy with blue-green light can be applied to reduce high concentrations of BR in blood and is used especially in the neonatal period. In this work, we studied the photochemistry of (Z)-isovinylneoxanthobilirubic acid methyl ester, a dipyrrinone subunit of BR, by steady-state absorption, femtosecond transient absorption, and stimulated Raman spectroscopies. Both the (Z)- and (E)-configurational isomers of isovinylneoxanthobilirubic acid undergo wavelength-dependent and reversible photoisomerization. The isomerization from the excited singlet state is ultrafast (the lifetimes of (Z)- and (E)-isomers were found to be ∼0.9 and 0.1 ps, respectively), and its efficiencies increase with increased photon energy. In addition, we studied sensitized photooxidation of the dipyrrinone subunit by singlet oxygen that leads to the formation of propentdyopents. Biological activities of these compounds, namely, effects on the superoxide production, lipoperoxidation, and tricarboxylic acid cycle metabolism, were also studied. Finally, different photochemical and biological properties of this BR subunit and its structural analogue, (Z)-vinylneoxanthobilirubic acid methyl ester, studied before, are discussed.
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Affiliation(s)
- Dominik Madea
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Taufiqueahmed Mujawar
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Aleš Dvořák
- Institute of Medical Biochemistry and Laboratory Diagnostics, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Na Bojišti 3, 121 08 Prague 2, Czech Republic
| | - Kateřina Pospíšilová
- Institute of Medical Biochemistry and Laboratory Diagnostics, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Na Bojišti 3, 121 08 Prague 2, Czech Republic
| | - Lucie Muchová
- Institute of Medical Biochemistry and Laboratory Diagnostics, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Na Bojišti 3, 121 08 Prague 2, Czech Republic
| | - Petra Čubáková
- Institute of Physics of the Czech Academy of Sciences, ELI Beamlines, Za Radnicí 835, 252 41 Dolní Břežany, Czech Republic.,University of South Bohemia in České Budějovice, Branišovská, 1645/31a, 370 05 České Budějovice, Czech Republic
| | - Miroslav Kloz
- University of South Bohemia in České Budějovice, Branišovská, 1645/31a, 370 05 České Budějovice, Czech Republic
| | - Jakub Švenda
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Libor Vítek
- Institute of Medical Biochemistry and Laboratory Diagnostics, and 4th Department of Internal Medicine, General University Hospital in Prague and 1st Faculty of Medicine, Charles University, Na Bojišti 3, 121 08 Prague 2, Czech Republic
| | - Petr Klán
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic.,RECETOX, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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18
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Biswas S, Kim J, Zhang X, Scholes GD. Coherent Two-Dimensional and Broadband Electronic Spectroscopies. Chem Rev 2022; 122:4257-4321. [PMID: 35037757 DOI: 10.1021/acs.chemrev.1c00623] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Over the past few decades, coherent broadband spectroscopy has been widely used to improve our understanding of ultrafast processes (e.g., photoinduced electron transfer, proton transfer, and proton-coupled electron transfer reactions) at femtosecond resolution. The advances in femtosecond laser technology along with the development of nonlinear multidimensional spectroscopy enabled further insights into ultrafast energy transfer and carrier relaxation processes in complex biological and material systems. New discoveries and interpretations have led to improved design principles for optimizing the photophysical properties of various artificial systems. In this review, we first provide a detailed theoretical framework of both coherent broadband and two-dimensional electronic spectroscopy (2DES). We then discuss a selection of experimental approaches and considerations of 2DES along with best practices for data processing and analysis. Finally, we review several examples where coherent broadband and 2DES were employed to reveal mechanisms of photoinitiated ultrafast processes in molecular, biological, and material systems. We end the review with a brief perspective on the future of the experimental techniques themselves and their potential to answer an even greater range of scientific questions.
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Affiliation(s)
- Somnath Biswas
- Department of Chemistry, Princeton University, Princeton, New Jersey 08 544, United States
| | - JunWoo Kim
- Department of Chemistry, Princeton University, Princeton, New Jersey 08 544, United States
| | - Xinzi Zhang
- Department of Chemistry, Princeton University, Princeton, New Jersey 08 544, United States
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08 544, United States
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19
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Beckwith JS, Aster A, Vauthey E. The excited-state dynamics of the radical anions of cyanoanthracenes. Phys Chem Chem Phys 2021; 24:568-577. [PMID: 34904984 PMCID: PMC8694058 DOI: 10.1039/d1cp04014f] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/29/2021] [Indexed: 12/03/2022]
Abstract
The radical anion of 9,10-dicyanoanthracene (DCA) has been suggested to be a promising chromophore for photoredox chemistry, due to its nanosecond excited-state lifetime determined from indirect measurements. Here, we investigate the excited-state dynamics of the radical anion of three cyanoanthracenes, including DCA˙-, produced by photoinduced electron transfer in liquid using both pump-probe and pump-pump probe transient electronic absorption spectroscopy. All three excited radical ions are characterised by a 3-5 ps lifetime, due to efficient non-radiative deactivation to the ground state. The decay pathway most probably involves D1/D0 conical intersection(s), whose presence is favoured by the enhanced flexibility of the radical anions relative to their neutral counterparts. The origin of the discrepancy with the nanosecond lifetime of DCA˙-* reported previously is discussed. These very short lifetimes limit, but do not preclude, photochemical applications of the cyanoanthracene anions.
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Affiliation(s)
- Joseph S Beckwith
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Alexander Aster
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland.
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20
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Zhang X, Lefebvre PL, Harvey JN. Effect of solvent motions on the dynamics of the Diels-Alder reaction. Phys Chem Chem Phys 2021; 24:1120-1130. [PMID: 34928279 DOI: 10.1039/d1cp05272a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
How solvent motions affect the dynamics of chemical reactions in which the solute undergoes a substantial shape change is a fundamental but elusive issue. This work utilizes reactive simulation and Grote-Hynes theory to explore the effect of solvent motions on the dynamics of the Diels-Alder reaction (in the reverse direction, this reaction involves very substantial solute expansion) in aprotic solvents. The results reveal that the solvent environment is not sufficiently constraining to influence transition state passage dynamics, with the calculated transmission coefficients being close to unity. Even when solvent motions are suppressed or artificially slowed down, the solvent only affects the reaction dynamics in the transition state region to a very small extent. The only notable effect of solvent occurs far from the transition state region and corresponds to caging of the reactants within the reactant well.
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Affiliation(s)
- Xiaoyong Zhang
- Theoretical and Computational Chemistry, Department of Chemistry, KU Leuven Celestijnenlaan 200F, 3001, Leuven, Belgium.
| | - Pierre-Louis Lefebvre
- Theoretical and Computational Chemistry, Department of Chemistry, KU Leuven Celestijnenlaan 200F, 3001, Leuven, Belgium. .,Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, USA
| | - Jeremy N Harvey
- Theoretical and Computational Chemistry, Department of Chemistry, KU Leuven Celestijnenlaan 200F, 3001, Leuven, Belgium.
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21
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Abstract
Photochemical reactions are increasingly being used for chemical and materials synthesis, for example, in photoredox catalysis, and generally involve photoexcitation of molecular chromophores dissolved in a liquid solvent. The choice of solvent influences the outcomes of the photochemistry because solute-solvent interactions modify the energies of and crossings between electronic states of the chromophores, and they affect the evolving structures of the photoexcited molecules. Ultrafast laser spectroscopy methods with femtosecond to picosecond time resolution can resolve the dynamics of these photoexcited molecules as they undergo structural and electronic changes, relax back to the ground state, dissipate their excess internal energy to the surrounding solvent, or undergo photochemical reactions. In this Account, we illustrate how experimental studies using ultrafast lasers can reveal the influences that different solvents or cosolutes exert on the photoinduced nonadiabatic dynamics of internal conversion and intersystem crossing in nonradiative relaxation pathways. Although the environment surrounding a solute molecule is rapidly changing, with fluctuations in the coordination to neighboring solvent molecules occurring on femtosecond or picosecond time scales, we show that it is possible to photoexcite selectively only those molecular chromophores transiently experiencing specific solute-solvent interactions such as intermolecular hydrogen bonding.The effects of different solvation environments on the photodynamics are illustrated using four selected examples of photochemical processes in which the solvent has a marked effect on the outcomes. We first consider two aromatic carbonyl compounds, benzophenone and acetophenone, which are known to undergo fast intersystem crossing to populate the first excited triplet state on time scales of a few picoseconds. We show that the nonadiabatic excited-state dynamics are modified by transient hydrogen bonding of the carbonyl group to a protic solvent or by coordination to a metal cation cosolute. We then examine how different solvents modify the competition between two alternative relaxation pathways in a photoexcited UVA-sunscreen molecule, diethylamino hydroxybenzoyl hexyl benzoate (DHHB). This relaxation back to the ground electronic state is an essential part of the effective operation of the sunscreen compound, but the dynamics are sensitive to the surrounding environment. Finally, we consider how solvents of different polarity affect the energies and lifetimes of excited states with locally excited or charge-transfer character in heterocyclic organic compounds used as excited-state electron donors for photoredox catalysis. With these and other examples, we seek to develop a molecular level understanding of how the choice of solution environment might be used to control the outcomes of photochemical reactions.
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Affiliation(s)
- Ravi Kumar Venkatraman
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | - Andrew J. Orr-Ewing
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
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22
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Abstract
The pathway of activationless proton transfer induced by an electron-transfer reaction is studied theoretically. Long-range electron transfer produces highly nonequilibrium medium polarization that can drive proton transfer through an activationless transition during the process of thermalization, dynamically altering the screening of the electron-proton Coulomb interaction by the medium. The cross electron-proton reorganization energy is the main energy parameter of the theory, which exceeds in magnitude the proton-transfer reorganization energy roughly by the ratio of the electron-transfer to proton-transfer distance. This parameter, which can be either positive or negative, is related to the difference in pKa values in two electron-transfer states. The relaxation time of the medium is on the (sub)picosecond time scale, which establishes the characteristic time for activationless proton transfer. Microscopic calculations predict substantial retardation of the collective relaxation dynamics compared to the continuum estimates due to the phenomenology analogous to de Gennes narrowing. Nonequilibrium medium configuration promoting proton transfer can be induced by either thermal or photoinduced charge transfer.
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Affiliation(s)
- Dmitry V Matyushov
- School of Molecular Sciences and Department of Physics, Arizona State University, P.O. Box 871504, Tempe, Arizona 85287-1504, United States
| | - Marshall D Newton
- Chemistry Department, Brookhaven National Laboratory, P.O. Box 5000, Upton, New York 11973-5000, United States
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23
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Smortsova Y, Miannay FA, Gustavsson T, Sauvage F, Ingrosso F, Kalugin O, Idrissi A. Interrogating the mechanism of the solvation dynamics in BmimBF4/PC mixtures: A cooperative study employing time-resolved fluorescence and molecular dynamics. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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24
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Yoneda Y, Kudisch B, Rather SR, Maiuri M, Nagasawa Y, Scholes GD, Miyasaka H. Vibrational Dephasing along the Reaction Coordinate of an Electron Transfer Reaction. J Am Chem Soc 2021; 143:14511-14522. [PMID: 34474559 DOI: 10.1021/jacs.1c01863] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of molecular vibration in photoinduced electron transfer (ET) reactions has been extensively debated in recent years. In this study, we investigated vibrational wavepacket dynamics in a model ET system consisting of an organic dye molecule as an electron acceptor dissolved in various electron donating solvents. By using broad band pump-probe (BBPP) spectroscopy with visible laser pulses of sub-10 fs duration, coherent vibrational wavepackets of naphthacene dye with frequencies spanning 170-1600 cm-1 were observed in the time domain. The coherence properties of 11 vibrational modes were analyzed by an inverse Fourier filtering procedure, and we discovered that the dephasing times of some vibrational coherences are reduced with increasing ET rates. Density functional theory calculations indicated that the corresponding vibrational modes have a large Huang-Rhys factor between the reactant and the product states, supporting the hypothesis that the loss of phase coherence along certain vibrational modes elucidates that those vibrations are coupled to the reaction coordinate of an ET reaction.
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Affiliation(s)
- Yusuke Yoneda
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Bryan Kudisch
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Shahnawaz R. Rather
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Margherita Maiuri
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Yutaka Nagasawa
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu 525-8577, Japan
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Hiroshi Miyasaka
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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25
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Zhou M, Jin R. Optical Properties and Excited-State Dynamics of Atomically Precise Gold Nanoclusters. Annu Rev Phys Chem 2021; 72:121-142. [PMID: 33297734 DOI: 10.1146/annurev-physchem-090419-104921] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Understanding the excited-state dynamics of nanomaterials is essential to their applications in photoenergy storage and conversion. This review summarizes recent progress in the excited-state dynamics of atomically precise gold (Au) nanoclusters (NCs). We first discuss the electronic structure and typical relaxation pathways of Au NCs from subpicoseconds to microseconds. Unlike plasmonic Au nanoparticles, in which collective electron excitation dominates, Au NCs show single-electron transitions and molecule-like exciton dynamics. The size-, shape-, structure-, and composition-dependent dynamics in Au NCs are further discussed in detail. For small-sized Au NCs, strong quantum confinement effects give rise to relaxation dynamics that is significantly dependent on atomic packing, shape, and heteroatom doping. For relatively larger-sized Au NCs, strong size dependence can be observed in exciton and electron dynamics. We also discuss the origin of coherent oscillations and their roles in excited-state relaxation. Finally, we provide our perspective on future directions in this area.
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Affiliation(s)
- Meng Zhou
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA;
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA;
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26
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Aster A, Rumble C, Bornhof AB, Huang HH, Sakai N, Šolomek T, Matile S, Vauthey E. Long-lived triplet charge-separated state in naphthalenediimide based donor-acceptor systems. Chem Sci 2021; 12:4908-4915. [PMID: 34168763 PMCID: PMC8179635 DOI: 10.1039/d1sc00285f] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
1,4,5,8-Naphthalenediimides (NDIs) are widely used motifs to design multichromophoric architectures due to their ease of functionalisation, their high oxidative power and the stability of their radical anion. The NDI building block can be incorporated in supramolecular systems by either core or imide functionalization. We report on the charge-transfer dynamics of a series of electron donor-acceptor dyads consisting of a NDI chromophore with one or two donors linked at the axial, imide position. Photo-population of the core-centred π-π* state is followed by ultrafast electron transfer from the electron donor to the NDI. Due to a solvent dependent singlet-triplet equilibrium inherent to the NDI core, both singlet and triplet charge-separated states are populated. We demonstrate that long-lived charge separation in the triplet state can be achieved by controlling the mutual orientation of the donor-acceptor sub-units. By extending this study to a supramolecular NDI-based cage, we also show that the triplet charge-separation yield can be increased by tuning the environment.
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Affiliation(s)
- Alexander Aster
- Department of Physical Chemistry, University of Geneva CH-1211 Geneva Switzerland
| | - Christopher Rumble
- Department of Physical Chemistry, University of Geneva CH-1211 Geneva Switzerland
| | - Anna-Bea Bornhof
- Department of Organic Chemistry, University of Geneva CH-1211 Geneva Switzerland
| | - Hsin-Hua Huang
- Department of Chemistry, University of Basel St. Johanns-Ring 19 Basel 4056 Switzerland
| | - Naomi Sakai
- Department of Organic Chemistry, University of Geneva CH-1211 Geneva Switzerland
| | - Tomáš Šolomek
- Department of Chemistry, University of Basel St. Johanns-Ring 19 Basel 4056 Switzerland
| | - Stefan Matile
- Department of Organic Chemistry, University of Geneva CH-1211 Geneva Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva CH-1211 Geneva Switzerland
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27
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Aster A, Bornhof AB, Sakai N, Matile S, Vauthey E. Lifetime Broadening and Impulsive Generation of Vibrational Coherence Triggered by Ultrafast Electron Transfer. J Phys Chem Lett 2021; 12:1052-1057. [PMID: 33470820 DOI: 10.1021/acs.jpclett.0c03641] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The absorption band shape of chromophores in liquid solution at room temperature is usually dominated by pure electronic dephasing dynamics, which occurs on the sub-100 fs time scale. Herein, we report on a series of dyads consisting of a naphthalenediimide (NDI) electron acceptor with one or two phenyl-based donors for which photoinduced intramolecular electron transfer is fast enough to be competitive with pure electronic dephasing. As a consequence, the absorption band of the π-π* transition of these dyads is broader than that of the NDI alone to an extent that scales with the electron transfer rate. Additionally, this reaction is so fast that it leads to the impulsive excitation of a low-frequency vibrational mode of the charge-separated product. Quantum-chemical calculations suggest that this vibration involves the C-N donor-acceptor bond, which shortens considerably upon electron transfer.
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Affiliation(s)
- Alexander Aster
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Anna-Bea Bornhof
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Naomi Sakai
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Stefan Matile
- Department of Organic Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva, Switzerland
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28
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Keanini RG, Dahlberg J, Tkacik PT. On the physical mechanisms underlying single molecule dynamics in simple liquids. Sci Rep 2021; 11:2528. [PMID: 33510369 PMCID: PMC7843658 DOI: 10.1038/s41598-021-82112-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 12/29/2020] [Indexed: 12/01/2022] Open
Abstract
Physical arguments and comparisons with published experimental data suggest that in simple liquids: (i) single-molecule-scale viscous forces are produced by temperature-dependent London dispersion forces, (ii) viscosity decay with increasing temperature reflects electron cloud compression and attendant suppression of electron screening, produced by increased nuclear agitation, and (iii) temperature-dependent self-diffusion is driven by a narrow band of phonon frequencies lying at the low-frequency end of the solid-state-like phonon spectrum. The results suggest that collision-induced electron cloud distortion plays a decisive role in single molecule dynamics: (i) electron cloud compression produces short-lived repulsive states and single molecule, self-diffusive hops, while (ii) shear-induced distortion generates viscosity and single-molecule-scale viscous drag. The results provide new insight into nonequilibrium molecular dynamics in nonpolar, nonmetallic liquids.
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Affiliation(s)
- Russell G Keanini
- Department of Mechanical Engineering, University of North Carolina at Charlotte, Charlotte, 28078, USA.
| | - Jerry Dahlberg
- Department of Mechanical Engineering, University of North Carolina at Charlotte, Charlotte, 28078, USA
| | - Peter T Tkacik
- Department of Mechanical Engineering, University of North Carolina at Charlotte, Charlotte, 28078, USA
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29
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Kretz B, Egger DA. Accurate Molecular Geometries in Complex Excited-State Potential Energy Surfaces from Time-Dependent Density Functional Theory. J Chem Theory Comput 2021; 17:357-366. [PMID: 33284603 DOI: 10.1021/acs.jctc.0c00858] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The interplay of electronic excitations and structural changes in molecules impacts nonradiative decay and charge transfer in the excited state, thus influencing excited-state lifetimes and photocatalytic reaction rates in optoelectronic and energy devices. To capture such effects requires computational methods providing an accurate description of excited-state potential energy surfaces and geometries. We suggest time-dependent density functional theory using optimally tuned range-separated hybrid (OT-RSH) functionals as an accurate approach to obtain excited-state molecular geometries. We show that OT-RSH provides accurate molecular geometries in excited-state potential energy surfaces that are complex and involve an interplay of local and charge-transfer excitations, for which conventional semilocal and hybrid functionals fail. At the same time, the nonempirical OT-RSH approach maintains the high accuracy of parametrized functionals (e.g., B3LYP) for predicting excited-state geometries of small organic molecules showing valence excited states.
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Affiliation(s)
- Bernhard Kretz
- Department of Physics, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - David A Egger
- Department of Physics, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
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30
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Paul S, Govind C, Karunakaran V. Planarity and Length of the Bridge Control Rate and Efficiency of Intramolecular Singlet Fission in Pentacene Dimers. J Phys Chem B 2020; 125:231-239. [PMID: 33371685 DOI: 10.1021/acs.jpcb.0c08590] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Singlet fission (SF) improves the power conversion efficiency of optoelectronic devices by converting high-energy photons into two triplet excitons. SF dynamics and efficiency (Φ) are controlled by various factors. Here, the effect of planarity and length of the bridge in pentacene dimers on the intramolecular SF (iSF) process was investigated by synthesizing the dimers connected by bridges having fluorene (FL-PD, planar), methyl-substituted biphenyl (MBP-PD, twisted), and diphenyl acetylene (DPA-PD, longer) groups and characterizing their excited-state relaxation dynamics using nanosecond and femtosecond pump-probe spectroscopy. Transient absorption studies reveal that iSF dynamics of FL-PD having a planar bridge are ∼787 times faster (187 ps) and exhibit higher Φ (198%) by feasible electronic coupling, compared to MBP-PD possessing a twisted bridge showing a low Φ of ∼16%. However compared to FL-PD, iSF dynamics of DPA-PD with an increase of bridge length are slower by an order (1.09 ns) and show comparable Φ of 185% through extended conjugation. Thus, the planarity and length of the bridge in pentacene dimers control the rate and efficiency of the iSF process.
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Affiliation(s)
- Sumitha Paul
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019 Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Chinju Govind
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019 Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
| | - Venugopal Karunakaran
- Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695 019 Kerala, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-Human Resource Development Centre, Ghaziabad, Uttar Pradesh 201 002, India
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31
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Romi S, Fanetti S, Bini R. Accessing the Activation Mechanisms of Ethylene Photo-Polymerization under Pressure by Transient Infrared Absorption Spectroscopy. J Phys Chem B 2020; 124:8149-8157. [PMID: 32846090 DOI: 10.1021/acs.jpcb.0c06244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ambient temperature photoinduced polymerization of compressed (P < 1 GPa) fluid ethylene was characterized by transient infrared absorption spectroscopy with a resolution of few nanoseconds, 3 orders of magnitude higher than previously reported. The reaction has been studied under both one- and two-photon excitation evidencing in the latter case its occurrence only in the presence of different transition metal oxides. Their photocatalytic activity is ascribed to the stabilization of the excited biradicals through electron density exchange between the d orbitals of the metal and the π antibonding orbitals of ethylene which lengthens the lifetime of the biradicals. In both one- and two-photon activation cases the polymerization is characterized by an initial step distinguished by a molecularity of 0.15 ± 0.02 identified as the activation step of the reaction lasting, in the one-photon excitation case, a few hundreds of nanoseconds. Using pulsed excitation the reaction evolves toward a free radical polymerization only under one-photon excitation whereas the critical concentration of radicals required to propagate the reaction is never achieved in the two-photon excitation case. Comparison with continuous wave excitation unambiguously identifies in the average power released to the sample the key factor to drive quantitatively and qualitatively the polymerization.
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Affiliation(s)
- Sebastiano Romi
- LENS, European Laboratory for Non-linear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy
| | - Samuele Fanetti
- LENS, European Laboratory for Non-linear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy.,Istituto di Chimica dei Composti OrganoMetallici, ICCOM, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Firenze, Italy
| | - Roberto Bini
- LENS, European Laboratory for Non-linear Spectroscopy, Via N. Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy.,Istituto di Chimica dei Composti OrganoMetallici, ICCOM, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Firenze, Italy.,Dipartimento di Chimica "Ugo Schiff", Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino, Italy
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32
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Lu J, Lee Y, Anna JM. Extracting the Frequency-Dependent Dynamic Stokes Shift from Two-Dimensional Electronic Spectra with Prominent Vibrational Coherences. J Phys Chem B 2020; 124:8857-8867. [DOI: 10.1021/acs.jpcb.0c05522] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Jiawei Lu
- University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania 19104, United States
| | - Yumin Lee
- University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania 19104, United States
| | - Jessica M. Anna
- University of Pennsylvania, 231 South 34 Street, Philadelphia, Pennsylvania 19104, United States
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33
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Nançoz C, Rumble C, Rosspeintner A, Vauthey E. Bimolecular photoinduced electron transfer in non-polar solvents beyond the diffusion limit. J Chem Phys 2020; 152:244501. [PMID: 32610996 DOI: 10.1063/5.0012363] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Electron transfer (ET) quenching dynamics in non-polar solvents are investigated using ultrafast spectroscopy with a series of six fluorophore/quencher pairs, covering a driving force range of more than 1.3 eV. The intrinsic ET rate constants, k0, deduced from the quenching dynamics in the static regime, are of the order of 1012-1013 M-1 s-1, i.e., at least as large as in acetonitrile, and do not exhibit any marked dependence on the driving force. A combination of transient electronic and vibrational absorption spectroscopy measurements reveals that the primary product of static quenching is a strongly coupled exciplex that decays within a few picoseconds. More weakly coupled exciplexes with a longer lifetime are generated subsequently, during the dynamic, diffusion-controlled, stage of the quenching. The results suggest that static ET quenching in non-polar solvents should be viewed as an internal conversion from a locally excited state to a charge-transfer state of a supermolecule rather than as a non-adiabatic ET process.
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Affiliation(s)
- Christoph Nançoz
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
| | - Christopher Rumble
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
| | - Arnulf Rosspeintner
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
| | - Eric Vauthey
- Department of Physical Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
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34
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Heller ER, Richardson JO. Semiclassical instanton formulation of Marcus–Levich–Jortner theory. J Chem Phys 2020; 152:244117. [DOI: 10.1063/5.0013521] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Eric R. Heller
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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35
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Sneha M, Lewis-Borrell L, Shchepanovska D, Bhattacherjee A, Tyler J, Orr-Ewing AJ. Solvent-dependent photochemical dynamics of a phenoxazine-based photoredox catalyst. ACTA ACUST UNITED AC 2020. [DOI: 10.1515/zpch-2020-1624] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
Organic substitutes for ruthenium and iridium complexes are increasingly finding applications in chemical syntheses involving photoredox catalysis. However, the performance of these organic compounds as electron-transfer photocatalysts depends on their accessible photochemical pathways and excited state lifetimes. Here, the UV-induced dynamics of N-phenyl phenoxazine, chosen as a prototypical N-aryl phenoxazine organic photoredox catalyst, are explored in three solvents, N,N-dimethyl formamide, dichloromethane and toluene, using ultrafast transient absorption spectroscopy. Quantum chemistry calculations reveal the locally excited or charge-transfer electronic character of the excited states, and are used to assign the transient electronic and vibrational bands observed. In toluene-d8, complete ground-state recovery is (31 ± 3) % by internal conversion (IC) from the photo-excited state (or from S1 after IC but before complete vibrational relaxation), (13 ± 2) % via direct decay from vibrationally relaxed S1 (most likely radiative decay, with an estimated radiative lifetime of 13 ns) and (56 ± 3) % via the T1 state (with intersystem crossing (ISC) rate coefficient k
ISC = (3.3 ± 0.2) × 108 s−1). In dichloromethane, we find evidence for excited state N-phenyl phenoxazine reaction with the solvent. Excited state lifetimes, ISC rates, and ground-state recovery show only modest variation with changes to the solvent environment because of the locally excited character of the S1 and T1 states.
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Affiliation(s)
- Mahima Sneha
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Luke Lewis-Borrell
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Darya Shchepanovska
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Aditi Bhattacherjee
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Jasper Tyler
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
| | - Andrew J. Orr-Ewing
- School of Chemistry , University of Bristol , Cantock’s Close , BS8 1TS , Bristol , UK
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36
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Jonely M, Noriega R. Role of Polar Protic Solvents in the Dissociation and Reactivity of Photogenerated Radical Ion Pairs. J Phys Chem B 2020; 124:3083-3089. [PMID: 32239936 DOI: 10.1021/acs.jpcb.9b11299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The UV photolysis of bimolecular charge transfer complexes is employed to yield reactive radical ions in their solvent-equilibrated electronic ground state. In polar protic media, noncovalent complexes of 1,2,4,5-tetracyanobenzene and toluene undergo efficient, ultrafast dissociation to ion pairs and equilibrate with their solvent environment before the resulting radical ions engage in electron transfer and proton abstraction on subnanosecond time scales. Solvent molecules play a critical role in these reactive pathways and in the dissociation and relaxation processes that precede them. We report a clear separation of time scales for these relaxation and reactive processes, which implies that solvent-solute interactions can be used as a tool for tuning the reaction pathways of equilibrated radical ions in solution.
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Affiliation(s)
- McKenzie Jonely
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake City, Utah 84112, United States
| | - Rodrigo Noriega
- Department of Chemistry, University of Utah, 315 S. 1400 E, Salt Lake City, Utah 84112, United States
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37
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Heller ER, Richardson JO. Instanton formulation of Fermi’s golden rule in the Marcus inverted regime. J Chem Phys 2020; 152:034106. [DOI: 10.1063/1.5137823] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Eric R. Heller
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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38
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Integrating ultrafast and stochastic dynamics studies of Brownian motion in molecular systems and colloidal particles. Curr Opin Colloid Interface Sci 2019. [DOI: 10.1016/j.cocis.2019.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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39
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Collins MI, McCamey DR, Tayebjee MJY. Fluctuating exchange interactions enable quintet multiexciton formation in singlet fission. J Chem Phys 2019; 151:164104. [PMID: 31675884 DOI: 10.1063/1.5115816] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Several recent electron spin resonance studies have observed a quintet multiexciton state during the singlet fission process. Here, we provide a general theoretical explanation for the generation of this state by invoking a time-varying exchange coupling between pairs of triplet excitons and subsequently solving the relevant time-varying spin Hamiltonian for different rates at which the exchange coupling varies. We simulate experimental ESR spectra and draw qualitative conclusions about the adiabatic and diabatic transitions between triplet pair spin states.
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Affiliation(s)
- Miles I Collins
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Dane R McCamey
- ARC Centre of Excellence in Exciton Science, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Murad J Y Tayebjee
- School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
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40
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Das Mahanta D, Islam SI, Choudhury S, Das DK, Mitra RK, Barman A. Contrasting hydration dynamics in DME and DMSO aqueous solutions: A combined optical pump-probe and GHz-THz dielectric relaxation investigation. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111194] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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41
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Otolski CJ, Mohan Raj A, Sharma G, Prabhakar R, Ramamurthy V, Elles CG. Ultrafast trans → cis Photoisomerization Dynamics of Alkyl-Substituted Stilbenes in a Supramolecular Capsule. J Phys Chem A 2019; 123:5061-5071. [PMID: 31140802 DOI: 10.1021/acs.jpca.9b03285] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ultrafast spectroscopy reveals the effects of confinement on the excited-state photoisomerization dynamics for a series of alkyl-substituted trans-stilbenes encapsulated in the hydrophobic cavity of an aqueous supramolecular organic host-guest complex. Compared with the solvated compounds, encapsulated trans-stilbenes have broader excited-state absorption spectra, excited-state lifetimes that are 3-4 times longer, and photoisomerization quantum yields that are 1.7-6.5 times lower in the restricted environment. The organic capsule disrupts the equilibrium structure and restricts torsional rotation around the central C═C double bond in the excited state, which is an important motion for the relaxation of trans-stilbene from S1 to S0. The location and identity of alkyl substituents play a significant role in determining the excited-state dynamics and photoisomerization quantum yields by tuning the relative crowding inside the capsule. The results are discussed in terms of distortions of the ground- and excited-state potential energy surfaces, including the topology of the S1-S0 conical intersection.
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Affiliation(s)
- Christopher J Otolski
- Department of Chemistry , University of Kansas , Lawrence , Kansas 66045 , United States
| | - A Mohan Raj
- Department of Chemistry , University of Miami , Coral Gables , Florida 33146 , United States
| | - Gaurav Sharma
- Department of Chemistry , University of Miami , Coral Gables , Florida 33146 , United States
| | - Rajeev Prabhakar
- Department of Chemistry , University of Miami , Coral Gables , Florida 33146 , United States
| | | | - Christopher G Elles
- Department of Chemistry , University of Kansas , Lawrence , Kansas 66045 , United States
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42
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Balevičius V, Wei T, Di Tommaso D, Abramavicius D, Hauer J, Polívka T, Duffy CDP. The full dynamics of energy relaxation in large organic molecules: from photo-excitation to solvent heating. Chem Sci 2019; 10:4792-4804. [PMID: 31183032 PMCID: PMC6521204 DOI: 10.1039/c9sc00410f] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/29/2019] [Indexed: 01/04/2023] Open
Abstract
In some molecular systems, such as nucleobases, polyenes or sunscreens, substantial amounts of photo-excitation energy are dissipated on a sub-picosecond time scale. Where does this energy go or among which degrees of freedom it is being distributed at such early times?
In some molecular systems, such as nucleobases, polyenes or the active ingredients of sunscreens, substantial amounts of photo-excitation energy are dissipated on a sub-picosecond time scale, raising questions such as: where does this energy go or among which degrees of freedom it is being distributed at such early times? Here we use transient absorption spectroscopy to track excitation energy dispersing from the optically accessible vibronic subsystem into the remaining vibrational subsystem of the solute and solvent. Monitoring the flow of energy during vibrational redistribution enables quantification of local molecular heating. Subsequent heat dissipation away from the solute molecule is characterized by classical thermodynamics and molecular dynamics simulations. Hence, we present a holistic approach that tracks the internal temperature and vibronic distribution from the act of photo-excitation to the restoration of the global equilibrium. Within this framework internal vibrational redistribution and vibrational cooling are emergent phenomena. We demonstrate the validity of the framework by examining a highly controversial example, carotenoids. We show that correctly accounting for the local temperature unambiguously explains their energetically and temporally congested spectral dynamics without the ad hoc postulation of additional ‘dark’ states. An immediate further application of this approach would be to monitor the excitation and thermal dynamics of pigment–protein systems.
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Affiliation(s)
- Vytautas Balevičius
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Tiejun Wei
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Devis Di Tommaso
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
| | - Darius Abramavicius
- Institute of Chemical Physics , Vilnius University , Sauletekio av. 9 , Vilnius , LT-10222 , Lithuania
| | - Jürgen Hauer
- Fakultät für Chemie , Technical University of Munich , Lichtenbergstraße 4 , D-85748 Garching , Germany.,Photonics Institute , TU Wien , Gußhausstraße 27 , 1040 Vienna , Austria
| | - Tomas Polívka
- Institute of Physics and Biophysics , Faculty of Science , University of South Bohemia , Branišovská 1760 , 37005 České Budějovice , Czech Republic
| | - Christopher D P Duffy
- School of Chemical and Biological Sciences , Queen Mary University of London , Mile End Road , London E1 4NS , UK .
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43
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Picconi D, Cina JA, Burghardt I. Quantum dynamics and spectroscopy of dihalogens in solid matrices. I. Efficient simulation of the photodynamics of the embedded I 2Kr 18 cluster using the G-MCTDH method. J Chem Phys 2019; 150:064111. [PMID: 30770011 DOI: 10.1063/1.5082650] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The molecular dynamics following the electronic BΠu30+⟵XΣg+1 photoexcitation of the iodine molecule embedded in solid krypton are studied quantum mechanically using the Gaussian variant of the multiconfigurational time-dependent Hartree method (G-MCTDH). The accuracy of the Gaussian wave packet approximation is validated against numerically exact MCTDH simulations for a fully anharmonic seven-dimensional model of the I2Kr18 cluster in a crystal Kr cage. The linear absorption spectrum, time-evolving vibrational probability densities, and I2 energy expectation value are accurately reproduced by the numerically efficient G-MCTDH approach. The reduced density matrix of the chromophore is analyzed in the coordinate, Wigner and energy representations, so as to obtain a multifaceted dynamical view of the guest-host interactions. Vibrational coherences extending over the bond distance range 2.7 Å < RI-I < 4.0 Å are found to survive for several vibrational periods, despite extensive dissipation. The present results prepare the ground for the simulation of time-resolved coherent Raman spectroscopy of the I2-krypton system addressed in Paper II.
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Affiliation(s)
- David Picconi
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt am Main, Germany
| | - Jeffrey A Cina
- Department of Chemistry and Biochemistry, and Oregon Center for Optical, Molecular, and Quantum Science, University of Oregon, Eugene, Oregon 97403, USA
| | - Irene Burghardt
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Straße 7, D-60438 Frankfurt am Main, Germany
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44
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Rather SR, Scholes GD. From Fundamental Theories to Quantum Coherences in Electron Transfer. J Am Chem Soc 2019; 141:708-722. [PMID: 30412671 DOI: 10.1021/jacs.8b09059] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Photoinduced electron transfer (ET) is a cornerstone of energy transduction from light to chemistry. The past decade has seen tremendous advances in the possible role of quantum coherent effects in the light-initiated energy and ET processes in chemical, biological, and materials systems. The prevalence of such coherence effects holds a promise to increase the efficiency and robustness of transport even in the face of energetic or structural disorder. A primary motive of this Perspective is to work out how to think about "coherence" in ET reactions. We will discuss how the interplay of basic parameters governing ET reactions-like electronic coupling, interactions with the environment, and intramolecular high-frequency quantum vibrations-impact coherences. This includes revisiting the insights from the seminal work on the theory of ET and time-resolved measurements on coherent dynamics to explore the role of coherences in ET reactions. We conclude by suggesting that in addition to optical spectroscopies, validating the functional role of coherences would require simultaneous mapping of correlated electron motion and atomically resolved nuclear structure.
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Affiliation(s)
- Shahnawaz R. Rather
- Frick Chemistry Laboratory , Princeton University , Princeton , New Jersey 08544 , United States
| | - Gregory D Scholes
- Frick Chemistry Laboratory , Princeton University , Princeton , New Jersey 08544 , United States
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45
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Zhang W, Liu XS, Yan L, Zhu GB, Wang ZH, Yang YQ. Photo-induced intermolecular electron transfer-effect of acceptor molecular structures. CHINESE J CHEM PHYS 2018. [DOI: 10.1063/1674-0068/31/cjcp1807171] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Wei Zhang
- Department of Physics, Harbin institute of Technology, Harbin 150001, China
| | - Xiao-song Liu
- Department of Physics, Harbin institute of Technology, Harbin 150001, China
| | - Lin Yan
- Department of Physics, Harbin institute of Technology, Harbin 150001, China
| | - Gang-bei Zhu
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900, China
| | - Zan-hao Wang
- Department of Physics, Harbin institute of Technology, Harbin 150001, China
| | - Yan-qiang Yang
- Department of Physics, Harbin institute of Technology, Harbin 150001, China
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900, China
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46
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Bruder L, Bangert U, Binz M, Uhl D, Vexiau R, Bouloufa-Maafa N, Dulieu O, Stienkemeier F. Coherent multidimensional spectroscopy of dilute gas-phase nanosystems. Nat Commun 2018; 9:4823. [PMID: 30446649 PMCID: PMC6240067 DOI: 10.1038/s41467-018-07292-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/25/2018] [Indexed: 12/20/2022] Open
Abstract
Two-dimensional electronic spectroscopy (2DES) is one of the most powerful spectroscopic techniques with unique sensitivity to couplings, coherence properties and real-time dynamics of a quantum system. While successfully applied to a variety of condensed phase samples, high precision experiments on isolated systems in the gas phase have been so far precluded by insufficient sensitivity. However, such experiments are essential for a precise understanding of fundamental mechanisms and to avoid misinterpretations. Here, we solve this issue by extending 2DES to isolated nanosystems in the gas phase prepared by helium nanodroplet isolation in a molecular beam-type experiment. This approach uniquely provides high flexibility in synthesizing tailored, quantum state-selected model systems of single and many-body character. In a model study of weakly-bound Rb2 and Rb3 molecules we demonstrate the method's unique capacity to elucidate interactions and dynamics in tailored quantum systems, thereby also bridging the gap to experiments in ultracold quantum science.
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Affiliation(s)
- Lukas Bruder
- Institute of Physics, University of Freiburg, 79104, Freiburg, Germany.
| | - Ulrich Bangert
- Institute of Physics, University of Freiburg, 79104, Freiburg, Germany
| | - Marcel Binz
- Institute of Physics, University of Freiburg, 79104, Freiburg, Germany
| | - Daniel Uhl
- Institute of Physics, University of Freiburg, 79104, Freiburg, Germany
| | - Romain Vexiau
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405, Orsay Cedex, France
| | - Nadia Bouloufa-Maafa
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405, Orsay Cedex, France
| | - Olivier Dulieu
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405, Orsay Cedex, France
| | - Frank Stienkemeier
- Institute of Physics, University of Freiburg, 79104, Freiburg, Germany.,Freiburg Institute of Advanced Studies (FRIAS), University of Freiburg, Albertstr. 19, 79194, Freiburg, Germany
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47
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Garcia-Meseguer R, Carpenter BK. Re-Evaluating the Transition State for Reactions in Solution. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800841] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Barry K. Carpenter
- School of Chemistry; Cardiff University; CF10 3AT Cardiff United Kingdom
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Sheng W, Nairat M, Pawlaczyk PD, Mroczka E, Farris B, Pines E, Geiger JH, Borhan B, Dantus M. Ultrafast Dynamics of a “Super” Photobase. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201806787] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Wei Sheng
- Department of Chemistry Michigan State University E. Lansing MI 48824 USA
| | - Muath Nairat
- Department of Chemistry Michigan State University E. Lansing MI 48824 USA
| | | | - Elizabeth Mroczka
- Department of Chemistry Michigan State University E. Lansing MI 48824 USA
| | - Benjamin Farris
- Department of Chemistry Michigan State University E. Lansing MI 48824 USA
| | - Ehud Pines
- Department of Chemistry Ben-Gurion University of the Negev POB 653 Beer Sheva 84105 Israel
| | - James H. Geiger
- Department of Chemistry Michigan State University E. Lansing MI 48824 USA
| | - Babak Borhan
- Department of Chemistry Michigan State University E. Lansing MI 48824 USA
| | - Marcos Dantus
- Department of Chemistry Michigan State University E. Lansing MI 48824 USA
- Department of Physics and Astronomy Michigan State University East Lansing MI 48824 USA
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49
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Sheng W, Nairat M, Pawlaczyk PD, Mroczka E, Farris B, Pines E, Geiger JH, Borhan B, Dantus M. Ultrafast Dynamics of a "Super" Photobase. Angew Chem Int Ed Engl 2018; 57:14742-14746. [PMID: 30152115 DOI: 10.1002/anie.201806787] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/26/2018] [Indexed: 11/08/2022]
Abstract
Molecular reactivity can change dramatically with the absorption of a photon due to the difference of the electronic configurations between the excited and ground states. Here we report on the discovery of a modular system (Schiff base formed from an aldehyde and an amine) that upon photoexcitation yields a more basic imine capable of intermolecular proton transfer from protic solvents. Ultrafast dynamics of the excited state conjugated Schiff base reveals the pathway for proton transfer, culminating in a 14-unit increase in pKa to give the excited state pKa * >20 in ethanol.
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Affiliation(s)
- Wei Sheng
- Department of Chemistry, Michigan State University, E. Lansing, MI, 48824, USA
| | - Muath Nairat
- Department of Chemistry, Michigan State University, E. Lansing, MI, 48824, USA
| | - Patrick D Pawlaczyk
- Department of Chemistry, Michigan State University, E. Lansing, MI, 48824, USA
| | - Elizabeth Mroczka
- Department of Chemistry, Michigan State University, E. Lansing, MI, 48824, USA
| | - Benjamin Farris
- Department of Chemistry, Michigan State University, E. Lansing, MI, 48824, USA
| | - Ehud Pines
- Department of Chemistry, Ben-Gurion University of the Negev, POB 653, Beer Sheva, 84105, Israel
| | - James H Geiger
- Department of Chemistry, Michigan State University, E. Lansing, MI, 48824, USA
| | - Babak Borhan
- Department of Chemistry, Michigan State University, E. Lansing, MI, 48824, USA
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, E. Lansing, MI, 48824, USA.,Department of Physics and Astronomy, Michigan State University, East Lansing, MI, 48824, USA
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50
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Datko BD, Livshits MY, Zhang Z, Portlock D, Qin Y, Rack JJ, Grey JK. Unravelling the enigma of ultrafast excited state relaxation in non-emissive aggregating conjugated polymers. Phys Chem Chem Phys 2018; 20:22159-22167. [PMID: 30116824 DOI: 10.1039/c8cp04061c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate a class of non-emissive conjugated polymers with very short excited state lifetimes believed to undergo singlet fission and relaxation to mid-gap forbidden excited states. Poly(3-decylthieneylenvinylene) (P3DTV) and its heavy atom analog, poly(3-decylseleneylenvinylene) (P3DSV), are strongly aggregating conjugated polymers that experience large excited state displacements along multiple vibrational modes. We demonstrate this Franck-Condon vibrational activity effectively disperses excitation energy into multiple non-radiative channels that can be explained using a simple, two-state potential energy surface model. Resonance Raman spectroscopy is sensitive to early Franck-Condon vibrational activity and we observe rich harmonic progressions involving multiple high frequency CC backbone symmetric stretching motions (∼1000-1600 cm-1) in both systems reflecting mode-specific excited state geometrical displacements. Transient absorption spectra confirm that efficient non-radiative processes dominate excited state relaxation dynamics which are confined to π-stacked aggregated chains. Surprisingly, we found little influence of the heteroatom consistent with efficient vibrational energy dissipation. Our results highlight the importance of aggregation and multi-dimensional Franck-Condon vibrational dynamics on the ability to harvest excitons, which are not usually considered in materials design and optimization schemes.
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Affiliation(s)
- Benjamin D Datko
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131, USA.
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