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Kokkin DL, Reilly NJ, Ivanov M, Rathore R, Reid SA. Excitonic Coupling in Fluorene-Based Bichromophoric Systems: Vibrational Quenching and the Transition from Weak to Intermediate Coupling. J Phys Chem A 2023; 127:7198-7204. [PMID: 37594308 DOI: 10.1021/acs.jpca.3c03511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/19/2023]
Abstract
Excimeric systems (i.e., excited dimers) have well served as model compounds for the study of the delocalization of electronic energy over weakly interacting chromophores. However, there remain relatively few isolated systems in which such interactions can be studied experimentally at a level to afford detailed comparisons with theory. In this Article, we examine a series of covalently and noncovalently linked dimers of fluorene, as a model aromatic chromophore, where the formation of excimers requires a π-stacked, cofacial orientation at van der Waals contact. Building upon a series of seminal prior studies that examined vibronic quenching of the excitation interaction in van der Waals dimers, the key question that we sought to address here is whether a single quenching factor could reproduce experimental excitonic splittings across a series of covalently and noncovalently linked bichromophoric systems built from the same chromophore. In comparing experimentally measured excitonic splittings with calculated static splittings using time-dependent density functional methods, we find that all systems save one fall on a line with a slope of 0.080(8), reflecting a vibrational quenching of roughly 1 order of magnitude. The outlier, which shows a significantly reduced quenching factor, represents a cyclophane-linked system where the fluorene moieties are constrained in a cofacial arrangement. We argue that this system evidences the transition from the weak to intermediate coupling regime.
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Affiliation(s)
- Damian L Kokkin
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, United States
| | - Neil J Reilly
- Department of Chemistry, University of Massachusetts-Boston, Boston, Massachusetts 02125, United States
| | - Maxim Ivanov
- Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, California 91320, United States
| | | | - Scott A Reid
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53233, United States
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Sidhardh GL, Ajith A, Sebastian E, Hariharan M, Shaji A. Local Phonon Environment as a Design Element for Long-Lived Excitonic Coherence: Dithia-anthracenophane Revisited. J Phys Chem A 2022; 126:3765-3773. [PMID: 35666186 DOI: 10.1021/acs.jpca.2c00507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The purpose of this study is to investigate the role of a structured immediate phonon environment in determining the exciton dynamics and the possibility of using it as an optimal design element. Through the case study of dithia-anthracenophane, a bichromophore using the Hierarchical Equations Of Motion formalism, we show that the experimentally observed coherent exciton dynamics can be reproduced only by considering the actual structure of the phonon environment. While the slow dephasing of quantum coherence in dithia-anthracenophane can be attributed to strong vibronic coupling to high-frequency modes, vibronic quenching is the source of long oscillation periods in population transfer. This study sheds light on the crucial role of the structure of the immediate phonon environment in determining the exciton dynamics. We conclude by proposing some design principles for sustaining long-lived coherence in molecular systems.
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Affiliation(s)
- Govind Lal Sidhardh
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Adithi Ajith
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Ebin Sebastian
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
| | - Anil Shaji
- School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala 695551, India
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Goswami S, Kopec S, Köppel H. Vibronic Coupling and Excitation Transfer in Hydrogen-Bonded Molecular Dimers: A Quantum Dynamical Analysis. J Phys Chem A 2019; 123:5491-5503. [DOI: 10.1021/acs.jpca.9b04903] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sugata Goswami
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Sabine Kopec
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Horst Köppel
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
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Vdovin A, Karpiuk E, Lipkowski J, Listkowski A, Kijak M, Grabowska A, Sepioł J. 2,5-bis(2′-benzoxazolyl)hydroquinone (BBHQ), a dually fluorescent ESIPT system revisited: XRD analysis and supersonic jet studies of deuterated species. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.06.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Franck Condon spectra of the 2-tolunitrile dimer and the binary 2-tolunitrile water cluster in the gas phase. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.04.092] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Inokuchi Y, Kida M, Ebata T. Geometric and Electronic Structures of Dibenzo-15-Crown-5 Complexes with Alkali Metal Ions Studied by UV Photodissociation and UV–UV Hole-Burning Spectroscopy. J Phys Chem A 2017; 121:954-962. [DOI: 10.1021/acs.jpca.6b09653] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yoshiya Inokuchi
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Motoki Kida
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Takayuki Ebata
- Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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Balmer FA, Kopec S, Köppel H, Leutwyler S. Excitonic Splitting and Vibronic Coupling Analysis of the m-Cyanophenol Dimer. J Phys Chem A 2016; 121:73-87. [DOI: 10.1021/acs.jpca.6b10416] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Franziska A. Balmer
- Department
of Chemistry and Biochemistry, University of Bern, Freiestrasse
3, CH-3012 Bern, Switzerland
| | - Sabine Kopec
- Theoretische
Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Horst Köppel
- Theoretische
Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
| | - Samuel Leutwyler
- Department
of Chemistry and Biochemistry, University of Bern, Freiestrasse
3, CH-3012 Bern, Switzerland
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Becucci M, Melandri S. High-Resolution Spectroscopic Studies of Complexes Formed by Medium-Size Organic Molecules. Chem Rev 2016; 116:5014-37. [DOI: 10.1021/acs.chemrev.5b00512] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Maurizio Becucci
- Department
of Chemistry “Ugo Schiff” and European Laboratory for
Nonlinear Spectroscopy, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Firenze, Italy
| | - Sonia Melandri
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, Via Francesco Selmi 2, 40126 Bologna, Italy
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Ottiger P, Köppel H, Leutwyler S. Excitonic splittings in molecular dimers: why static ab initio calculations cannot match them. Chem Sci 2015; 6:6059-6068. [PMID: 29435210 PMCID: PMC5802277 DOI: 10.1039/c5sc02546j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 08/26/2015] [Indexed: 01/25/2023] Open
Abstract
After decades of research on molecular excitons, only few molecular dimers are available on which exciton and vibronic coupling theories can be rigorously tested. In centrosymmetric H-bonded dimers consisting of identical (hetero)aromatic chromophores, the monomer electronic transition dipole moment vectors subtract or add, yielding S0 → S1 and S0 → S2 transitions that are symmetry-forbidden or -allowed, respectively. Symmetry breaking by 12C/13C or H/D isotopic substitution renders the forbidden transition weakly allowed. The excitonic coupling (Davydov splitting) can then be measured between the S0 → S1 and S0 → S2 vibrationless bands. We discuss the mass-specific excitonic spectra of five H-bonded dimers that are supersonically cooled to a few K and investigated using two-color resonant two-photon ionization spectroscopy. The excitonic splittings Δcalc predicted by ab initio methods are 5-25 times larger than the experimental excitonic splittings Δexp. The purely electronic ab initio splittings need to be reduced ("quenched"), reflecting the coupling of the electronic transition to the optically active vibrations of the monomers. The so-called quenching factors Γ < 1 can be determined from experiment (Γexp) and/or calculation (Γcalc). The vibronically quenched splittings Γ·Δcalc are found to nicely reproduce the experimental exciton splittings.
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Affiliation(s)
- Philipp Ottiger
- Dept. für Chemie und Biochemie , Freiestrasse 3 , CH-3012 Bern , Switzerland . ; ; Tel: +41 31 631 4479
| | - Horst Köppel
- Physikalisch-Chemisches Institut , Universität Heidelberg , Im Neuenheimer Feld 229 , D-69120 Heidelberg , Germany
| | - Samuel Leutwyler
- Dept. für Chemie und Biochemie , Freiestrasse 3 , CH-3012 Bern , Switzerland . ; ; Tel: +41 31 631 4479
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Kopec S, Ottiger P, Leutwyler S, Köppel H. Analysis of the S2←S0 vibronic spectrum of the ortho-cyanophenol dimer using a multimode vibronic coupling approach. J Chem Phys 2015; 142:084308. [DOI: 10.1063/1.4913363] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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