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Scognamiglio A, Thalmann KS, Hartweg S, Rendler N, Bruder L, Coto PB, Thoss M, Stienkemeier F. Non-adiabatic electronic relaxation of tetracene from its brightest singlet excited state. J Chem Phys 2024; 161:024302. [PMID: 38973758 DOI: 10.1063/5.0214006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 06/16/2024] [Indexed: 07/09/2024] Open
Abstract
The ultrafast relaxation dynamics of tetracene following UV excitation to the bright singlet state S6 has been studied with time-resolved photoelectron spectroscopy. With the help of high-level ab initio multireference perturbation theory calculations, we assign photoelectron signals to intermediate dark electronic states S3, S4, and S5 as well as to a low-lying electronic state S2. The energetic structure of these dark states has not been determined experimentally previously. The time-dependent photoelectron yields assigned to the states S6, S5, and S4 have been analyzed and reveal the depopulation of S6 within 60 fs, while S5 and S4 are populated with delays of about 50 and 80 fs. The dynamics of the lower-lying states S3 and S2 seem to agree with a delayed population coinciding with the depopulation of the higher-lying states S4-S6 but could not be elucidated in full detail due to the low signal levels of the corresponding two-photon ionization probe processes.
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Affiliation(s)
- A Scognamiglio
- University of Freiburg, Institute of Physics, Hermann-Herder-Str. 3, Freiburg, Germany
| | - K S Thalmann
- University of Freiburg, Institute of Physics, Hermann-Herder-Str. 3, Freiburg, Germany
| | - S Hartweg
- University of Freiburg, Institute of Physics, Hermann-Herder-Str. 3, Freiburg, Germany
| | - N Rendler
- University of Freiburg, Institute of Physics, Hermann-Herder-Str. 3, Freiburg, Germany
| | - L Bruder
- University of Freiburg, Institute of Physics, Hermann-Herder-Str. 3, Freiburg, Germany
| | - P B Coto
- Materials Physics Center (CFM), CSIC and Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 5, 20018 Donostia-San Sebastián, Spain
| | - M Thoss
- University of Freiburg, Institute of Physics, Hermann-Herder-Str. 3, Freiburg, Germany
| | - F Stienkemeier
- University of Freiburg, Institute of Physics, Hermann-Herder-Str. 3, Freiburg, Germany
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Webster IJ, Beckham JL, Johnson ND, Duncan MA. Photochemical Synthesis and Spectroscopy of Covalent PAH Dimers. J Phys Chem A 2022; 126:1144-1157. [PMID: 35152698 DOI: 10.1021/acs.jpca.1c10606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Laser photochemistry of pressed-pellet samples of polycyclic aromatic hydrocarbons (PAHs) produces covalently bonded dimers and some higher polymers. This chemistry was discovered initially via laser desorption time-of-flight mass spectrometry experiments, which produced masses (m/z) of 2M-2 and 2M-4 (where M is the monomer parent mass). Dimers are believed to be formed from photochemical dehydrogenation and radical polymerization chemistry in the desorption plume. Replication of these ablation conditions at higher throughput allowed PAH dimers of pyrene, perylene, and coronene to be produced and collected in milligram quantities. Differential sublimation provided purification of the dimers and elimination of residual monomers. The purified dimers were investigated with UV-visible, IR, and Raman spectroscopy, complemented by computational studies using density functional theory at the CAM-B3LYP/def2-TZV level. Calculations and predicted spectra were calibrated by comparison with the corresponding monomers and used to determine the lowest energy dimer structures. Infrared and Raman spectroscopy provided few distinctive signatures, but UV-visible spectra detected new transitions for each dimer. The comparison of simulated and experimental spectra allows determination of the most prevalent structures for the PAH dimers. The work presented here provides interesting insights into the spectroscopy of extended aromatic systems and a new strategy for the photochemical synthesis of large PAH dimers.
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Affiliation(s)
- Ian J Webster
- Department of Chemistry, University of Georgia, Athens 30602-2556, Georgia
| | - Jacob L Beckham
- Department of Chemistry, University of Georgia, Athens 30602-2556, Georgia
| | - Natalie D Johnson
- Department of Chemistry, University of Georgia, Athens 30602-2556, Georgia
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens 30602-2556, Georgia
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3
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Kanno M, Mignolet B, Remacle F, Kono H. Identification of an ultrafast internal conversion pathway of pyrazine by time-resolved vacuum ultraviolet photoelectron spectrum simulations. J Chem Phys 2021; 154:224304. [PMID: 34241214 DOI: 10.1063/5.0048900] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The internal conversion from the optically bright S2 (1B2u, ππ*) state to the dark S1 (1B3u, nπ*) state in pyrazine is a standard benchmark for experimental and theoretical studies on ultrafast radiationless decay. Since 2008, a few theoretical groups have suggested significant contributions of other dark states S3 (1Au, nπ*) and S4 (1B2g, nπ*) to the decay of S2. We have previously reported the results of nuclear wave packet simulations [Kanno et al., Phys. Chem. Chem. Phys. 17, 2012 (2015)] and photoelectron spectrum calculations [Mignolet et al., Chem. Phys. 515, 704 (2018)] that support the conventional two-state picture. In this article, the two different approaches, i.e., wave packet simulation and photoelectron spectrum calculation, are combined: We computed the time-resolved vacuum ultraviolet photoelectron spectrum and photoelectron angular distribution for the ionization of the wave packet transferred from S2 to S1. The present results reproduce almost all the characteristic features of the corresponding experimental time-resolved spectrum [Horio et al., J. Chem. Phys. 145, 044306 (2016)], such as a rapid change from a three-band to two-band structure. This further supports the existence and character of the widely accepted pathway (S2 → S1) of ultrafast internal conversion in pyrazine.
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Affiliation(s)
- Manabu Kanno
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Benoît Mignolet
- Theoretical Physical Chemistry, UR MOLSYS, University of Liège, B4000 Liège, Belgium
| | - Françoise Remacle
- Theoretical Physical Chemistry, UR MOLSYS, University of Liège, B4000 Liège, Belgium
| | - Hirohiko Kono
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
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Electronic excited states of benzene in interaction with water clusters: influence of structure and size. Theor Chem Acc 2021. [DOI: 10.1007/s00214-021-02764-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mestdagh JM, Poisson L. Excited State Dynamics of Isolated 6- and 8-Hydroxyquinoline Molecules. Chemphyschem 2020; 21:2605-2613. [PMID: 33022865 DOI: 10.1002/cphc.202000626] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/05/2020] [Indexed: 11/09/2022]
Abstract
The photoinduced dynamics of isolated n-hydroxyquinoline (nHQ) molecules (n=6,8) was investigated in femtosecond pump-probe experiments. A qualitative difference was found between 8HQ and 6HQ. After an initial rapid decay corresponding to the departure of the initial wavepacket out of the Franck-Condon region of the excitation, the 8HQ probe signal decays to zero in 0.37 ps whereas a much longer time constant of 10.4 ps is observed in 6HQ. This interrogates on the role played by the intramolecular H-bond N · · · HO which is at play the 8HQ molecule. Ab-initio were performed at the MCSCF/aug-cc-pVDZ level on the 8HQ molecule to help the discussion. A complex energy landscape was found, which includes a conical intersection.
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Affiliation(s)
- Jean-Michel Mestdagh
- LIDYL, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
| | - Lionel Poisson
- LIDYL, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191, Gif-sur-Yvette, France
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Yamada T, Ito N, Kawakita N, Kato HS, Munakata T. Formation and regulation of unoccupied hybridized band with image potential states at perylene/graphite interface. J Chem Phys 2019; 151:224703. [DOI: 10.1063/1.5126373] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Takashi Yamada
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
| | - Natsumi Ito
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
| | - Noriaki Kawakita
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
| | - Hiroyuki S. Kato
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
| | - Toshiaki Munakata
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan
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Flock M, Bosse L, Kaiser D, Engels B, Fischer I. A time-resolved photoelectron imaging study on isolated tolane: observation of the biradicalic 1A u state. Phys Chem Chem Phys 2019; 21:13157-13164. [PMID: 31173002 DOI: 10.1039/c9cp02222h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tolane (diphenylacetylene, C14H10) was studied by picosecond time-resolved photoionisation and photoelectron imaging in a supersonic jet. The low-energy part of the 1B1u← S0 REMPI spectrum is very similar to an earlier LIF spectrum, however additional bands were observed at higher energies above the fluorescence cut-off. For a number of bands the dynamics were investigated via pump-probe photoionisation and photoelectron spectroscopy. Around the 1B1u origin the lifetimes are in the ns range, but they drop to some 10 ps at higher excitation energies. For the short-lived bands at higher energies a sequential two-step relaxation to a long-lived electronic state was observed proceeding via an intermediately populated state with a lifetime of 100-200 ps. By comparison with previous quantum chemical calculations we assign this state as the biradicalic trans-bent1Au state that is ionised in a two-photon process.
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Affiliation(s)
- Marco Flock
- Institute of Physical and Theoretical Chemistry, University of Wuerzburg, 97074 Wuerzburg, Germany.
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Yamada T, Kawakita N, Okui C, Munakata T. Hybridization of an unoccupied molecular orbital with an image potential state at a lead phthalocyanine/graphite interface. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:044004. [PMID: 30523835 DOI: 10.1088/1361-648x/aaf08e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The interaction of a molecular orbital with a surface state is important to understand the spatial distribution of the wave function at the molecule/substrate interface. In this study, we focus on hybridization of an unoccupied state of lead phthalocyanine (PbPc) with the image potential state (IPS) on a graphite surface. The hybridization modifies the energy-momentum dispersions of the IPS on PbPc films as observed by angle-resolved two-photon photoemission. On the PbPc 1 monolayer film, the IPS band forms a band gap and back-folding appears at the first Brillouin zone boundary due to the periodic potential by the adsorbate lattice. The modification of the dispersion is accompanied by the intensity enhancement of the IPS. We attributed the origin of the modified dispersion and intensity enhancement to a hybridization of the IPS with a molecule-derived unoccupied level. From the photon energy-dependent measurement on multilayer films, we have found the diffuse unoccupied molecular level in the vicinity of the IPS. The tail part of the IPS wave function in the substrate is enhanced by the hybridization with the unoccupied state, and thus strengthens the transition from the occupied substrate band to the hybridized IPS.
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Noble JA, Aupetit C, Descamps D, Petit S, Simon A, Mascetti J, Ben Amor N, Blanchet V. Ultrafast electronic relaxations from the S3 state of pyrene. Phys Chem Chem Phys 2019; 21:14111-14125. [DOI: 10.1039/c8cp06895j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The ultrafast relaxation occurring in pyrene upon excitation at 4.68 eV was studied in a supersonic gas-jet fs pump–probe experiment.
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Affiliation(s)
| | | | | | - Stéphane Petit
- Université de Bordeaux-CNRS-CEA, CELIA, UMR5107
- F33405 Talence
- France
| | - Aude Simon
- Université de Toulouse-CNRS-UT3, LCPQ-IRSAMC
- F-31062 Toulouse
- France
| | | | - Nadia Ben Amor
- Université de Toulouse-CNRS-UT3, LCPQ-IRSAMC
- F-31062 Toulouse
- France
| | - Valérie Blanchet
- Université de Bordeaux-CNRS-CEA, CELIA, UMR5107
- F33405 Talence
- France
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Yamada T, Kinoshita M, Araragi K, Watanabe Y, Ueba T, Kato HS, Munakata T. Direct visualization of diffuse unoccupied molecular orbitals at a rubrene/graphite interface. Phys Chem Chem Phys 2018; 20:17415-17422. [DOI: 10.1039/c8cp01796d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Using a combination of spectroscopic and microscopic imaging techniques, localized and delocalized unoccupied states are visualized at the molecular level.
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Affiliation(s)
- Takashi Yamada
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka 560-0043
- Japan
| | - Mariko Kinoshita
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka 560-0043
- Japan
| | - Kento Araragi
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka 560-0043
- Japan
| | - Yu Watanabe
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka 560-0043
- Japan
| | - Takahiro Ueba
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka 560-0043
- Japan
| | - Hiroyuki S. Kato
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka 560-0043
- Japan
| | - Toshiaki Munakata
- Department of Chemistry
- Graduate School of Science
- Osaka University
- Toyonaka 560-0043
- Japan
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