1
|
Jadoun D, Kowalewski M. Coherent x-ray spontaneous emission spectroscopy of conical intersections. J Chem Phys 2024; 160:094102. [PMID: 38426516 DOI: 10.1063/5.0180976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 02/16/2024] [Indexed: 03/02/2024] Open
Abstract
Conical intersections are known to play a vital role in many photochemical processes. The breakdown of the Born-Oppenheimer approximation in the vicinity of a conical intersection causes exciting phenomena, such as the ultrafast radiationless decay of excited states. The passage of a molecule through a conical intersection creates a coherent superposition of electronic states via nonadiabatic couplings. Detecting this coherent superposition may serve as a direct probe of the conical intersection. In this paper, we theoretically demonstrate the use of coherent spontaneous emission in samples with long-range order for probing the occurrence of a conical intersection in a molecule. Our simulations show that the spectrum contains clear signatures of the created coherent superposition of electronic states. We investigate the bandwidth requirements for the x-ray probes, which influence the observation of coherent superposition generated by the conical intersection.
Collapse
Affiliation(s)
- Deependra Jadoun
- 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
| |
Collapse
|
2
|
Jadoun D, Zhang Z, Kowalewski M. Raman Spectroscopy of Conical Intersections Using Entangled Photons. J Phys Chem Lett 2024; 15:2023-2030. [PMID: 38349969 PMCID: PMC10895689 DOI: 10.1021/acs.jpclett.3c02852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/15/2024]
Abstract
Ultrafast Raman spectroscopy with attosecond pulses in the extreme ultraviolet and X-ray regime has been proposed theoretically for tracking the non-adiabatic dynamics of molecules in great detail. The large bandwidth of these pulses, which span several electronvolts within a couple of femtoseconds, provides a unique tool for tracking non-adiabatic phenomena. However, spectroscopy with classical light is limited by the time-bandwidth product of the probe laser pulse. In this work, we theoretically investigate an ultrafast Raman spectroscopy scheme that utilizes pairs of entangled photons. Our model simulations demonstrate that the dynamics in the vicinity of a conical intersection can be resolved with unprecedented resolution in the time and frequency domain.
Collapse
Affiliation(s)
- Deependra Jadoun
- Department
of Physics, Stockholm University, AlbaNova
University Center, SE-106 91 Stockholm, Sweden
| | - Zhedong Zhang
- Department
of Physics, City University of Hong Kong, Kowloon, Hong Kong SAR
- Shenzhen
Research Institute, City University of Hong
Kong, Shenzhen, Guangdong 518057, China
| | - Markus Kowalewski
- Department
of Physics, Stockholm University, AlbaNova
University Center, SE-106 91 Stockholm, Sweden
| |
Collapse
|
3
|
Keefer D, Cavaletto SM, Rouxel JR, Garavelli M, Yong H, Mukamel S. Ultrafast X-Ray Probes of Elementary Molecular Events. Annu Rev Phys Chem 2023; 74:73-97. [PMID: 37093660 DOI: 10.1146/annurev-physchem-062322-051532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Elementary events that determine photochemical outcomes and molecular functionalities happen on the femtosecond and subfemtosecond timescales. Among the most ubiquitous events are the nonadiabatic dynamics taking place at conical intersections. These facilitate ultrafast, nonradiative transitions between electronic states in molecules that can outcompete slower relaxation mechanisms such as fluorescence. The rise of ultrafast X-ray sources, which provide intense light pulses with ever-shorter durations and larger observation bandwidths, has fundamentally revolutionized our spectroscopic capabilities to detect conical intersections. Recent theoretical studies have demonstrated an entirely new signature emerging once a molecule traverses a conical intersection, giving detailed insights into the coupled nuclear and electronic motions that underlie, facilitate, and ultimately determine the ultrafast molecular dynamics. Following a summary of current sources and experiments, we survey these techniques and provide a unified overview of their capabilities. We discuss their potential to dramatically increase our understanding of ultrafast photochemistry.
Collapse
Affiliation(s)
- Daniel Keefer
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California, USA; ,
| | - Stefano M Cavaletto
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California, USA; ,
- Current affiliation: Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Jérémy R Rouxel
- Université de Lyon, UJM-Saint-Etienne, IOGS, Laboratoire Hubert Curien, UMR CNRS 5516, Saint-Etienne, France
| | - Marco Garavelli
- Dipartimento di Chimica Industriale, Università degli Studi di Bologna, Bologna, Italy
| | - Haiwang Yong
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California, USA; ,
| | - Shaul Mukamel
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California, USA; ,
| |
Collapse
|
4
|
Boeije Y, Olivucci M. From a one-mode to a multi-mode understanding of conical intersection mediated ultrafast organic photochemical reactions. Chem Soc Rev 2023; 52:2643-2687. [PMID: 36970950 DOI: 10.1039/d2cs00719c] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
This review discusses how ultrafast organic photochemical reactions are controlled by conical intersections, highlighting that decay to the ground-state at multiple points of the intersection space results in their multi-mode character.
Collapse
Affiliation(s)
- Yorrick Boeije
- Van 't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Massimo Olivucci
- Chemistry Department, University of Siena, Via Aldo Moro n. 2, 53100 Siena, Italy
- Chemistry Department, Bowling Green State University, Overman Hall, Bowling Green, Ohio 43403, USA
| |
Collapse
|
5
|
Schnappinger T, Jadoun D, Gudem M, Kowalewski M. Time-resolved X-ray and XUV based spectroscopic methods for nonadiabatic processes in photochemistry. Chem Commun (Camb) 2022; 58:12763-12781. [PMID: 36317595 PMCID: PMC9671098 DOI: 10.1039/d2cc04875b] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/21/2022] [Indexed: 11/03/2023]
Abstract
The photochemistry of numerous molecular systems is influenced by conical intersections (CIs). These omnipresent nonadiabatic phenomena provide ultra-fast radiationless relaxation channels by creating degeneracies between electronic states and decide over the final photoproducts. In their presence, the Born-Oppenheimer approximation breaks down, and the timescales of the electron and nuclear dynamics become comparable. Due to the ultra-fast dynamics and the complex interplay between nuclear and electronic degrees of freedom, the direct experimental observation of nonadiabatic processes close to CIs remains challenging. In this article, we give a theoretical perspective on novel spectroscopic techniques capable of observing clear signatures of CIs. We discuss methods that are based on ultra-short laser pulses in the extreme ultraviolet and X-ray regime, as their spectral and temporal resolution allow for resolving the ultra-fast dynamics near CIs.
Collapse
Affiliation(s)
- Thomas Schnappinger
- Department of Physics, Stockholm University, Albanova University Centre, SE-106 91 Stockholm, Sweden.
| | - 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.
| |
Collapse
|
6
|
Yong H, Rouxel JR, Keefer D, Mukamel S. Direct Monitoring of Conical Intersection Passage via Electronic Coherences in Twisted X-Ray Diffraction. PHYSICAL REVIEW LETTERS 2022; 129:103001. [PMID: 36112435 DOI: 10.1103/physrevlett.129.103001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/07/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
Quantum coherences in electronic motions play a critical role in determining the pathways and outcomes of virtually all photophysical and photochemical molecular processes. However, the direct observation of electronic coherences in the vicinity of conical intersections remains a formidable challenge. We propose a novel time-resolved twisted x-ray diffraction technique that can directly monitor the electronic coherences created as the molecule passes through a conical intersection. We show that the contribution of electronic populations to this signal is canceled out when using twisted x-ray beams that carry a light orbital angular momentum, providing a direct measurement of transient electronic coherences in gas-phase molecules.
Collapse
Affiliation(s)
- Haiwang Yong
- Department of Chemistry, University of California, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Jérémy R Rouxel
- University Lyon, UJM-Saint-Étienne, CNRS, Graduate School Optics Institute, Laboratoire Hubert Curien UMR 5516, Saint-Étienne 42023, France
| | - Daniel Keefer
- Department of Chemistry, University of California, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, California 92697, USA
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|