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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.
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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
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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.
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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
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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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Bäuml L, Rott F, Schnappinger T, de Vivie-Riedle R. Following the Nonadiabatic Ultrafast Dynamics of Uracil via Simulated X-ray Absorption Spectra. J Phys Chem A 2023; 127:9787-9796. [PMID: 37955656 DOI: 10.1021/acs.jpca.3c06509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
The nucleobase uracil exhibits high photostability due to ultrafast relaxation processes mediated by conical intersections (CoIns), where the interplay between nuclear and electron dynamics becomes crucial. In our previous study, we observed seemingly long-lived traces of electronic coherence for the relaxation process through the S2/S1 CoIn by applying our ansatz for coupled nuclear and electron dynamics in molecules (NEMol). In this work, we theoretically investigate how time-dependent transient X-ray absorption spectroscopy can be used to observe this ultrafast dynamics. Therefore, we calculated X-ray absorption spectra (XAS) for the oxygen K-edge, using a multireference protocol in combination with NEMol dynamics. Thus, we have access to both the transient XAS based on the nuclear wavepacket dynamics and the modulation of the signals caused by the electronic coherence induced by the excitation process and the presence of a CoIn seam. In both cases, we were able to qualitatively predict its influence on the resulting XAS.
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Affiliation(s)
- Lena Bäuml
- Department of Chemistry, LMU Munich, Munich 81377, Germany
| | - Florian Rott
- Department of Chemistry, LMU Munich, Munich 81377, Germany
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Talbot JJ, Arias-Martinez JE, Cotton SJ, Head-Gordon M. Fantastical excited state optimized structures and where to find them. J Chem Phys 2023; 159:171102. [PMID: 37916588 DOI: 10.1063/5.0172015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 10/16/2023] [Indexed: 11/03/2023] Open
Abstract
The quantum chemistry community has developed analytic forces for approximate electronic excited states to enable walking on excited state potential energy surfaces (PES). One can thereby computationally characterize excited state minima and saddle points. Always implicit in using this machinery is the fact that an excited state PES only exists within the realm of the Born-Oppenheimer approximation, where the nuclear and electronic degrees of freedom separate. This work demonstrates through ab initio calculations and simple nonadiabatic dynamics that some excited state minimum structures are fantastical: they appear to exist as stable configurations only as a consequence of the PES construct, rather than being physically observable. Each fantastical structure exhibits an unphysically high predicted harmonic frequency and associated force constant. This fact can serve as a valuable diagnostic of when an optimized excited state structure is non-observable. The origin of this phenomenon can be attributed to the coupling between different electronic states. As PESs approach one another, the upper surface can form a minimum that is very close to a near-touching point. The force constant, evaluated at this minimum, relates to the strength of the electronic coupling rather than to any characteristic excited state vibration. Nonadiabatic dynamics results using a Landau-Zener model illustrate that fantastical excited state structures have extremely short lifetimes on the order of a few femtoseconds. Their appearance in a calculation signals the presence of a nearby conical intersection through which the system will rapidly cross to a lower surface.
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Affiliation(s)
- Justin J Talbot
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA
| | - Juan E Arias-Martinez
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Stephen J Cotton
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA
| | - Martin Head-Gordon
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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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.
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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
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