1
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Qiang Y, Sun K, Palacino-González E, Shen K, Rao BJ, Gelin MF, Zhao Y. Probing avoided crossings and conical intersections by two-pulse femtosecond stimulated Raman spectroscopy: Theoretical study. J Chem Phys 2024; 160:054107. [PMID: 38341700 DOI: 10.1063/5.0186583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 01/15/2024] [Indexed: 02/13/2024] Open
Abstract
This study leverages two-pulse femtosecond stimulated Raman spectroscopy (2FSRS) to characterize molecular systems with avoided crossings (ACs) and conical intersections (CIs) in their low-lying excited electronic states. By simulating 2FSRS spectra of microscopically inspired ACs and CIs models, we demonstrate that 2FSRS not only delivers valuable information on the molecular parameters characterizing ACs and CIs but also helps distinguish between these two systems.
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Affiliation(s)
- Yijia Qiang
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Kewei Sun
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Elisa Palacino-González
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Kaijun Shen
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - B Jayachander Rao
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Maxim F Gelin
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Yang Zhao
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
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2
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Cho D, Gu B, Mukamel S. Optical Cavity Manipulation and Nonlinear UV Molecular Spectroscopy of Conical Intersections in Pyrazine. J Am Chem Soc 2022; 144:7758-7767. [PMID: 35404593 DOI: 10.1021/jacs.2c00921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Optical cavities provide a versatile platform for manipulating the excited-state dynamics of molecules via strong light-matter coupling. We employ optical absorption and two-multidimensional electronic spectroscopy simulations to investigate the effect of optical cavity coupling in the nonadiabatic dynamics of photoexcited pyrazine. We observe the emergence of a novel polaritonic conical intersection (PCI) between the electronic dark state and photonic surfaces as the cavity frequency is tuned. The PCI could significantly change the nonadiabatic dynamics of pyrazine by doubling the decay rate constant of the S2 state population. Moreover, the absorption spectrum and excited-state dynamics could be systematically manipulated by tuning the strong light-matter interaction, e.g., the cavity frequency and cavity coupling strength. We propose that a tunable optical cavity-molecule system may provide promising approaches for manipulating the photophysical properties of molecules.
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Affiliation(s)
- Daeheum Cho
- Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, Daegu 41566, South Korea
| | - Bing Gu
- Department of Chemistry and Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Shaul Mukamel
- Department of Chemistry and Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
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3
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Nam Y, Keefer D, Nenov A, Conti I, Aleotti F, Segatta F, Lee JY, Garavelli M, Mukamel S. Conical Intersection Passages of Molecules Probed by X-ray Diffraction and Stimulated Raman Spectroscopy. J Phys Chem Lett 2021; 12:12300-12309. [PMID: 34931839 DOI: 10.1021/acs.jpclett.1c03814] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Conical intersections (CoIns) play an important role in ultrafast relaxation channels. Their monitoring remains a formidable experimental challenge. We theoretically compare the probing of the S2 → S1 CoIn passage in 4-thiouracil by monitoring its vibronic coherences, using off-resonant X-ray-stimulated Raman spectroscopy (TRUECARS) and time-resolved X-ray diffraction (TRXD). The quantum nuclear wavepacket (WP) dynamics provides an accurate picture of the photoinduced dynamics. Upon photoexcitation, the WP oscillates among the Franck-Condon point, the S2 minimum, and the CoIn with a 70 fs period. A vibronic coherence first emerges at 20 fs and can be observed until the S2 state is fully depopulated. The distribution of the vibronic frequencies involved in the coherence is recorded by the TRUECARS spectrogram. The TRXD signal provides spatial images of electron densities associated with the CoIn. In combination, the two signals provide a complementary picture of the nonadiabatic passage, which helps in the study of the underlying photophysics in thiobases.
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Affiliation(s)
- Yeonsig Nam
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
- Convergence Research Center for Energy and Environmental Sciences, Sungkyunkwan University, Suwon 16419, Korea
| | - Daniel Keefer
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Artur Nenov
- Dipartimento di Chimica Industriale "Toso Montanari," Universita' degli Studi di Bologna, I-40136 Bologna, Italy
| | - Irene Conti
- Dipartimento di Chimica Industriale "Toso Montanari," Universita' degli Studi di Bologna, I-40136 Bologna, Italy
| | - Flavia Aleotti
- Dipartimento di Chimica Industriale "Toso Montanari," Universita' degli Studi di Bologna, I-40136 Bologna, Italy
| | - Francesco Segatta
- Dipartimento di Chimica Industriale "Toso Montanari," Universita' degli Studi di Bologna, I-40136 Bologna, Italy
| | - Jin Yong Lee
- Convergence Research Center for Energy and Environmental Sciences, Sungkyunkwan University, Suwon 16419, Korea
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Korea
| | - Marco Garavelli
- Dipartimento di Chimica Industriale "Toso Montanari," Universita' degli Studi di Bologna, I-40136 Bologna, Italy
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
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4
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Jadoun D, Gudem M, Kowalewski M. Capturing fingerprints of conical intersection: Complementary information of non-adiabatic dynamics from linear x-ray probes. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2021; 8:034101. [PMID: 33981781 PMCID: PMC8096460 DOI: 10.1063/4.0000093] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/08/2021] [Indexed: 05/09/2023]
Abstract
Many recent experimental ultrafast spectroscopy studies have hinted at non-adiabatic dynamics indicating the existence of conical intersections, but their direct observation remains a challenge. The rapid change of the energy gap between the electronic states complicated their observation by requiring bandwidths of several electron volts. In this manuscript, we propose to use the combined information of different x-ray pump-probe techniques to identify the conical intersection. We theoretically study the conical intersection in pyrrole using transient x-ray absorption, time-resolved x-ray spontaneous emission, and linear off-resonant Raman spectroscopy to gather evidence of the curve crossing.
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Affiliation(s)
- Deependra Jadoun
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden
| | - Mahesh Gudem
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden
| | - Markus Kowalewski
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden
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5
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Conti I, Cerullo G, Nenov A, Garavelli M. Ultrafast Spectroscopy of Photoactive Molecular Systems from First Principles: Where We Stand Today and Where We Are Going. J Am Chem Soc 2020; 142:16117-16139. [PMID: 32841559 PMCID: PMC7901644 DOI: 10.1021/jacs.0c04952] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
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Computational spectroscopy is becoming a mandatory tool for the interpretation of the
complex, and often congested, spectral maps delivered by modern non-linear multi-pulse
techniques. The fields of Electronic Structure Methods,
Non-Adiabatic Molecular Dynamics, and Theoretical
Spectroscopy represent the three pillars of the virtual ultrafast
optical spectrometer, able to deliver transient spectra in
silico from first principles. A successful simulation strategy requires a
synergistic approach that balances between the three fields, each one having its very
own challenges and bottlenecks. The aim of this Perspective is to demonstrate that,
despite these challenges, an impressive agreement between theory and experiment is
achievable now regarding the modeling of ultrafast photoinduced processes in complex
molecular architectures. Beyond that, some key recent developments in the three fields
are presented that we believe will have major impacts on spectroscopic simulations in
the very near future. Potential directions of development, pending challenges, and
rising opportunities are illustrated.
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Affiliation(s)
- Irene Conti
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, IFN-CNR, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Artur Nenov
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
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6
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Cho D, Rouxel JR, Mukamel S. Stimulated X-ray Resonant Raman Spectroscopy of Conical Intersections in Thiophenol. J Phys Chem Lett 2020; 11:4292-4297. [PMID: 32370507 DOI: 10.1021/acs.jpclett.0c00949] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The conical intersection dynamics of thiophenol is studied by computing the stimulated X-ray resonant Raman spectroscopy signals. The hybrid probing field is constructed of a hard X-ray narrowband femtosecond pulse combined with an attosecond broadband X-ray pulse to provide optimal spectral and temporal resolutions for electronic coherences in the level crossing region. The signal carries phase information about the valence-core electronic coupling in the vicinity of conical intersections. Two conical intersections occurring during the course of the S-H dissociation dynamics can be distinguished by their valence-core transition frequencies computed at the complete active space self-consistent field level. The X-ray pulse is tuned such that the Raman transition at the first conical intersection between 1πσ* and 11ππ* involves higher core levels, while the Raman transition at the second conical intersection between 1πσ* and S0 involves the lowest core level in the sulfur K-edge.
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Affiliation(s)
- Daeheum Cho
- Department of Chemistry and Department of Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Jérémy R Rouxel
- Department of Chemistry and Department of Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Shaul Mukamel
- Department of Chemistry and Department of Physics & Astronomy, University of California, Irvine, California 92697-2025, United States
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7
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Abstract
The conical intersection dynamics of thiophenol is studied theoretically using the stimulated X-ray Raman imaging (SXRI) technique. SXRI employs a hard X-ray narrowband/broadband hybrid probe field and provides a real-time and real-space image of the passage through conical intersections. The signal, calculated using the minimal-coupling radiation/matter Hamiltonian, carries the phase information, and the real-space image of the transition charge density can be reconstructed by its Fourier transform. The two conical intersections (S2/S1 (11ππ*/1πσ*) and S1/S0 (1πσ*/S0)) can be distinguished and identified by the diffraction patterns in the level crossing regimes.
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Affiliation(s)
- Daeheum Cho
- Department of Chemistry , University of California , Irvine , California 92697-2025 , United States
| | - Shaul Mukamel
- Department of Chemistry , University of California , Irvine , California 92697-2025 , United States
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8
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Fang C, Tang L, Oscar BG, Chen C. Capturing Structural Snapshots during Photochemical Reactions with Ultrafast Raman Spectroscopy: From Materials Transformation to Biosensor Responses. J Phys Chem Lett 2018; 9:3253-3263. [PMID: 29799757 DOI: 10.1021/acs.jpclett.8b00373] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Chemistry studies the composition, structure, properties, and transformation of matter. A mechanistic understanding of the pertinent processes is required to translate fundamental knowledge into practical applications. The current development of ultrafast Raman as a powerful time-resolved vibrational technique, particularly femtosecond stimulated Raman spectroscopy (FSRS), has shed light on the structure-energy-function relationships of various photosensitive systems. This Perspective reviews recent work incorporating optical innovations, including the broad-band up-converted multicolor array (BUMA) into a tunable FSRS setup, and demonstrates its resolving power to watch metal speciation and photolysis, leading to high-quality thin films, and fluorescence modulation of chimeric protein biosensors for calcium ion imaging. We discuss advantages of performing FSRS in the mixed time-frequency domain and present strategies to delineate mechanisms by tracking low-frequency modes and systematically modifying chemical structures with specific functional groups. These unique insights at the chemical-bond level have started to enable the rational design and precise control of functional molecular machines in optical, materials, energy, and life sciences.
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Affiliation(s)
- Chong Fang
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Longteng Tang
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Breland G Oscar
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
| | - Cheng Chen
- Department of Chemistry , Oregon State University , 153 Gilbert Hall , Corvallis , Oregon 97331 , United States
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9
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Tempelaar R, Reichman DR. Generalization of fewest-switches surface hopping for coherences. J Chem Phys 2018; 148:102309. [DOI: 10.1063/1.5000843] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Roel Tempelaar
- Department of Chemistry, Columbia University, 3000 Broadway,
New York, New York 10027, USA
| | - David R. Reichman
- Department of Chemistry, Columbia University, 3000 Broadway,
New York, New York 10027, USA
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10
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Kowalewski M, Fingerhut BP, Dorfman KE, Bennett K, Mukamel S. Simulating Coherent Multidimensional Spectroscopy of Nonadiabatic Molecular Processes: From the Infrared to the X-ray Regime. Chem Rev 2017; 117:12165-12226. [DOI: 10.1021/acs.chemrev.7b00081] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Markus Kowalewski
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Benjamin P. Fingerhut
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
| | - Konstantin E. Dorfman
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Kochise Bennett
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
| | - Shaul Mukamel
- Department
of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, United States
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11
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Dijkstra AG, Prokhorenko VI. Simulation of photo-excited adenine in water with a hierarchy of equations of motion approach. J Chem Phys 2017; 147:064102. [DOI: 10.1063/1.4997433] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Arend G. Dijkstra
- University of Leeds, School of Chemistry and School of Physics and Astronomy, Leeds LS2 9JT, United Kingdom
| | - Valentyn I. Prokhorenko
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
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12
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Kowalewski M, Bennett K, Rouxel JR, Mukamel S. Monitoring Nonadiabatic Electron-Nuclear Dynamics in Molecules by Attosecond Streaking of Photoelectrons. PHYSICAL REVIEW LETTERS 2016; 117:043201. [PMID: 27494470 DOI: 10.1103/physrevlett.117.043201] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Indexed: 05/16/2023]
Abstract
Streaking of photoelectrons has long been used for the temporal characterization of attosecond extreme ultraviolet pulses. When the time-resolved photoelectrons originate from a coherent superposition of electronic states, they carry additional phase information, which can be retrieved by the streaking technique. In this contribution we extend the streaking formalism to include coupled electron and nuclear dynamics in molecules as well as initial coherences. We demonstrate how streaked photoelectrons offer a novel tool for monitoring nonadiabatic dynamics as it occurs in the vicinity of conical intersections and avoided crossings. Streaking can provide high time resolution direct signatures of electronic coherences, which affect many primary photochemical and biological events.
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Affiliation(s)
- Markus Kowalewski
- Department of Chemistry, Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, USA
| | - Kochise Bennett
- Department of Chemistry, Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, USA
| | - Jérémy R Rouxel
- Department of Chemistry, Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, USA
| | - Shaul Mukamel
- Department of Chemistry, Department of Physics and Astronomy, University of California, Irvine, California 92697-2025, USA
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13
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Dietze DR, Mathies RA. Femtosecond Stimulated Raman Spectroscopy. Chemphyschem 2016; 17:1224-51. [DOI: 10.1002/cphc.201600104] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Daniel R. Dietze
- Department of Chemistry; University of California in Berkeley; CA Berkeley 94720 USA
| | - Richard A. Mathies
- Department of Chemistry; University of California in Berkeley; CA Berkeley 94720 USA
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14
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Rao BJ, Gelin MF, Domcke W. Resonant Femtosecond Stimulated Raman Spectra: Theory and Simulations. J Phys Chem A 2016; 120:3286-95. [DOI: 10.1021/acs.jpca.5b12316] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. Jayachander Rao
- Departamento de Química,
and Centro de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - Maxim F. Gelin
- Department of Chemistry, Technische Universität München, D-85747 Garching, Germany
| | - Wolfgang Domcke
- Department of Chemistry, Technische Universität München, D-85747 Garching, Germany
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15
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Duan HG, Thorwart M. Quantum Mechanical Wave Packet Dynamics at a Conical Intersection with Strong Vibrational Dissipation. J Phys Chem Lett 2016; 7:382-386. [PMID: 26751091 DOI: 10.1021/acs.jpclett.5b02793] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We derive a reduced model for the nonadiabatic quantum dynamics of an electronic wave packet moving through a conical intersection in the presence of strong vibrational damping. Starting from the dissipative two-state two-model model, we transform the tuning and the coupling mode to the bath. The resulting quantum two-state model with two highly structured environments is solved numerically exactly in the regime of strong vibrational damping. We find negative cross peaks in the ultrafast optical 2D spectra as clear signatures of the conical intersection. They arise from secondary excitations of the wave packet after having passed through the photophysical energy funnel. This feature is in agreement with recent transient absorption measurements of rhodopsin.
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Affiliation(s)
- Hong-Guang Duan
- I. Institut für Theoretische Physik, Universität Hamburg , Jungiusstraße 9, 20355 Hamburg, Germany
- Max Planck-Institute for the Structure and Dynamics of Matter , Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging , Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Michael Thorwart
- I. Institut für Theoretische Physik, Universität Hamburg , Jungiusstraße 9, 20355 Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging , Luruper Chaussee 149, 22761 Hamburg, Germany
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16
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Bennett K, Kowalewski M, Mukamel S. Nonadiabatic Dynamics May Be Probed through Electronic Coherence in Time-Resolved Photoelectron Spectroscopy. J Chem Theory Comput 2016; 12:740-52. [DOI: 10.1021/acs.jctc.5b00824] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kochise Bennett
- Chemistry Department, University of California, Irvine, California 92697-2025, United States
| | - Markus Kowalewski
- Chemistry Department, University of California, Irvine, California 92697-2025, United States
| | - Shaul Mukamel
- Chemistry Department, University of California, Irvine, California 92697-2025, United States
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17
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Kowalewski M, Bennett K, Dorfman KE, Mukamel S. Catching Conical Intersections in the Act: Monitoring Transient Electronic Coherences by Attosecond Stimulated X-Ray Raman Signals. PHYSICAL REVIEW LETTERS 2015; 115:193003. [PMID: 26588377 DOI: 10.1103/physrevlett.115.193003] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Indexed: 05/23/2023]
Abstract
Conical intersections (CIs) dominate the pathways and outcomes of virtually all photophysical and photochemical molecular processes. Despite extensive experimental and theoretical effort, CIs have not been directly observed yet and the experimental evidence is being inferred from fast reaction rates and some vibrational signatures. We show that short x-ray (rather than optical) pulses can directly detect the passage through a CI with the adequate temporal and spectral sensitivity. The technique is based on a coherent Raman process that employs a composite femtosecond or attosecond x-ray pulse to detect the electronic coherences (rather than populations) that are generated as the system passes through the CI.
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Affiliation(s)
- Markus Kowalewski
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
| | - Kochise Bennett
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
| | - Konstantin E Dorfman
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
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