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Bejaoui S, Bera PP, Salama F, Lee T. Cavity Ring-Down Spectroscopy of Anthracene, 9-Methylanthracene, and 2-Methylanthracene in Supersonic Expansion. J Phys Chem A 2023; 127:2717-2730. [PMID: 36893328 DOI: 10.1021/acs.jpca.2c08994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
The S0-S1 absorption spectra of anthracene (C14H10), 9-methylanthracene (C15H12), and 2-methylanthracene (C15H12) are measured in the ultraviolet region between 330 and 375 nm (26,666 to 30,303 cm-1) with cavity ring-down spectroscopy in supersonic free-jet expansions of argon. The associated vibronic band systems and their spectroscopic assignments are discussed and compared to previous studies performed using fluorescence excitation and dispersed fluorescence techniques. Density functional theory (DFT) calculations were carried out to study the structures and evaluate the vibrational transitions of the ground and excited states. Time-dependent DFT calculations of the first electronic excited states and Franck-Condon factor calculations were carried out to assist in the assignment of the experimentally measured vibronic bands. The vibronic spectra obtained in absorption agree well with fluorescence excitation spectra in terms of peak positions but exhibit different relative band intensities. We find a very good match between experimentally obtained vibronic line positions and the peak positions of the quantum chemically calculated Franck-Condon excitation lines.
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Affiliation(s)
- Salma Bejaoui
- Bay Area Environmental Research Institute, Moffett Field, California 94035, United States.,Space Science and Astrobiology Division, NASA Ames Research Center, Mountain View, California 94035, United States
| | - Partha P Bera
- Bay Area Environmental Research Institute, Moffett Field, California 94035, United States.,Space Science and Astrobiology Division, NASA Ames Research Center, Mountain View, California 94035, United States
| | - Farid Salama
- Space Science and Astrobiology Division, NASA Ames Research Center, Mountain View, California 94035, United States
| | - Timothy Lee
- Space Science and Astrobiology Division, NASA Ames Research Center, Mountain View, California 94035, United States
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Abstract
Excimers play an important role in photochemical processes ranging from singlet fission to DNA damage, and the characteristic red-shift in fluorescence spectra associated with excimer formation can provide information about aggregate formation and the orientation of chromophores. When a mixture of chromophores is present, exciplex formation may lead to spectral characteristics distinct from those of either monomer or the corresponding excimers. To predict the effects of aggregation in a system containing a mixture of small acenes, binding energies and minimum-energy geometries have been calculated for three mixed S1 exciplexes. Benchmark CASSCF/NEVPT2 multireference binding energies of 18.2, 27.7, and 49.3 kJ/mol are reported for the benzene-naphthalene, benzene-anthracene, and naphthalene-anthracene exciplexes, respectively. TDDFT calculations have been performed using a range of exchange-correlation functionals, showing that many functionals perform inconsistently, and the error in binding energy often depends on the character of the monomer excitation from which the exciplex state is derived. Moderate exciplex stabilization observed for the benzene-naphthalene and naphthalene-anthracene exciplexes results from a mixture of charge transfer and exciton delocalization.
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Isomer-specific vibronic structure of the 9-, 1-, and 2-anthracenyl radicals via slow photoelectron velocity-map imaging. Proc Natl Acad Sci U S A 2016; 113:1698-705. [PMID: 26792521 DOI: 10.1073/pnas.1520862113] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polycyclic aromatic hydrocarbons, in various charge and protonation states, are key compounds relevant to combustion chemistry and astrochemistry. Here, we probe the vibrational and electronic spectroscopy of gas-phase 9-, 1-, and 2-anthracenyl radicals (C14H9) by photodetachment of the corresponding cryogenically cooled anions via slow photoelectron velocity-map imaging (cryo-SEVI). The use of a newly designed velocity-map imaging lens in combination with ion cooling yields photoelectron spectra with <2 cm(-1) resolution. Isomer selection of the anions is achieved using gas-phase synthesis techniques, resulting in observation and interpretation of detailed vibronic structure of the ground and lowest excited states for the three anthracenyl radical isomers. The ground-state bands yield electron affinities and vibrational frequencies for several Franck-Condon active modes of the 9-, 1-, and 2-anthracenyl radicals; term energies of the first excited states of these species are also measured. Spectra are interpreted through comparison with ab initio quantum chemistry calculations, Franck-Condon simulations, and calculations of threshold photodetachment cross sections and anisotropies. Experimental measures of the subtle differences in energetics and relative stabilities of these radical isomers are of interest from the perspective of fundamental physical organic chemistry and aid in understanding their behavior and reactivity in interstellar and combustion environments. Additionally, spectroscopic characterization of these species in the laboratory is essential for their potential identification in astrochemical data.
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Send R, Kühn M, Furche F. Assessing Excited State Methods by Adiabatic Excitation Energies. J Chem Theory Comput 2011; 7:2376-86. [DOI: 10.1021/ct200272b] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Robert Send
- Institut für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Michael Kühn
- Institut für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76131 Karlsruhe, Germany
| | - Filipp Furche
- Department of Chemistry, University of California—Irvine, 1102 Natural Sciences II, Irvine, California 92697-2025, United States
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Pentlehner D, Greil C, Dick B, Slenczka A. Line broadening in electronic spectra of anthracene derivatives inside superfluid helium nanodroplets. J Chem Phys 2010; 133:114505. [DOI: 10.1063/1.3479583] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- D Pentlehner
- Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg, Germany
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Rouillé G, Arold M, Staicu A, Henning T, Huisken F. Cavity Ring-Down Laser Absorption Spectroscopy of Jet-Cooled L-Tryptophan. J Phys Chem A 2009; 113:8187-94. [DOI: 10.1021/jp903253s] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gaël Rouillé
- Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena, Germany, and National Institute for Lasers, Plasma and Radiation Physics, Laser Department, P.O. Box MG-36, 077125 Magurele, Bucharest, Romania
| | - Marco Arold
- Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena, Germany, and National Institute for Lasers, Plasma and Radiation Physics, Laser Department, P.O. Box MG-36, 077125 Magurele, Bucharest, Romania
| | - Angela Staicu
- Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena, Germany, and National Institute for Lasers, Plasma and Radiation Physics, Laser Department, P.O. Box MG-36, 077125 Magurele, Bucharest, Romania
| | - Thomas Henning
- Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena, Germany, and National Institute for Lasers, Plasma and Radiation Physics, Laser Department, P.O. Box MG-36, 077125 Magurele, Bucharest, Romania
| | - Friedrich Huisken
- Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena, Germany, and National Institute for Lasers, Plasma and Radiation Physics, Laser Department, P.O. Box MG-36, 077125 Magurele, Bucharest, Romania
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Tan X. Towards a comprehensive electronic database of polycyclic aromatic hydrocarbons and its application in constraining the identities of possible carriers of the diffuse interstellar bands. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2009; 71:2005-2011. [PMID: 18790664 DOI: 10.1016/j.saa.2008.07.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 07/27/2008] [Indexed: 05/26/2023]
Abstract
A theoretical approach is developed to pre-select individual polycyclic aromatic hydrocarbons (PAHs) as possible carriers of the diffuse interstellar bands (DIBs). In this approach, a computer program is used to enumerate all PAH molecules with up to a specific number of fused benzene rings. Fast quantum chemical calculations are then employed to calculate the electronic transition energies, oscillator strengths, and rotational constants of these molecules. An electronic database of all PAHs with up to any specific number of benzene rings can be constructed this way. Comparison of the electronic transition energies, oscillator strengths, and rotational band contours of all PAHs in the database with astronomical spectra allows one to constrain the identities of individual PAHs as possible carriers of some of the intense narrow DIBs. Using the current database containing up to 10 benzene rings we have pre-selected 8 closed-shell PAHs as possible carriers of the famous lambda6614 DIB.
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Affiliation(s)
- Xiaofeng Tan
- X Scientific, Inc., 1000 Kiely Boulevard Unit 90, Santa Clara, CA 95051, United States.
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Staicu A, Rouillé G, Henning T, Huisken F, Pouladsaz D, Scholz R. S1←S0 transition of 2,3-benzofluorene at low temperatures in the gas phase. J Chem Phys 2008; 129:074302. [DOI: 10.1063/1.2967186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Husain MM, Tandon HC, Varadwaj PR. Singlet and doublet states UV-vis spectrum and electronic properties of 3-methylchrysene and 4-methylchrysene in glass matrix. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 69:693-700. [PMID: 17611146 DOI: 10.1016/j.saa.2007.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Revised: 05/09/2007] [Accepted: 05/09/2007] [Indexed: 05/16/2023]
Abstract
The ultraviolet-visual spectrum of 3-methylchrysene, 4-methylchrysene and their radical cations formed by ultraviolet radiations, were measured in glass matrix at the room temperature. In the measured singlet state spectrum we were able to identify the alpha, p, beta, beta' (Clar's) or (1)L(b), (1)L(a)(1)B(b), (1)B(a) (Platt's notation) bands. The presence of alpha, beta or (1)L(b), (1)B(b) was confirmed by calculating their wavelength ratio lambda(alpha)/lambda(beta). Since matrix induces perturbation in the measured spectrum; it becomes necessary to take into account the perturbation while computing the spectrum. An effort has been made in this work to simulate the electronic spectrum in the same environment as is measured. This study presents the first calculated spectrum of these systems and their cations in glass matrix by semi empirical methods. To observe the magnitude of perturbation and hence to see the spectral shift in glass matrix, the spectrum was calculated in the free state as well. Spectral properties such as frontier orbitals gap, dipole moment, mean polarizabilities and its tensors were also computed both in glass matrix and free state using semiemperical method. The measured bands of 3-methylchrysene cation at wavelength 416.50 and 473.85 nm closely match with the available diffuse intersteallar bands (DIBs) at 417.55 and 472.64 nm, respectively. Also the observed 474.85 nm band of 4-methylchrysene cation matches the DIB at 476.00 nm.
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Affiliation(s)
- Mudassir M Husain
- Physics Section, Department of Applied Sciences and Humanities, Faculty of Engineering and Technology, Jamia Millia Islamia (a Central University), New Delhi 110025, India.
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Bendkowsky V, Heinecke E, Hese A. High-resolution laser spectroscopy on the S1←S0 transition of jet-cooled anthracene: Rotational structure and Stark effect. J Chem Phys 2007; 127:224306. [DOI: 10.1063/1.2806184] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rouillé G, Arold M, Staicu A, Krasnokutski S, Huisken F, Henning T, Tan X, Salama F. S1(A11)←S0(A11) transition of benzo[g,h,i]perylene in supersonic jets and rare gas matrices. J Chem Phys 2007; 126:174311. [PMID: 17492867 DOI: 10.1063/1.2727467] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The study of the S1(1A1)<--S0(1A1) transition of benzo[g,h,i]perylene (BghiP, C22H12) in supersonic jets and solid rare gas matrices is reported. In the jet-cooled spectrum, the origin band position is located at 25,027.1+/-0.2 cm-1, the assignment being supported by the analysis of vibrational shifts and rotational band contours. Except for the origin band, which is weak, all bands are attributed to the fundamental excitation of nontotally symmetric b1 vibrational modes of S1. The intensity pattern is interpreted as a consequence of the weak oscillator strength of the electronic transition combined with intensity-borrowing through vibronic interaction between the S1(1A1) and S2(1B1) states. The spectra of the S1(1A1)<--S0(1A1) and S2(1B1)<--S0(1A1) transitions have also been measured for BghiP in solid neon and argon matrices. The comparison of the redshifts determined for either transition reveals that the polarizability of BghiP is larger in its S2 than in its S1 state. Bandwidths of 2.7 cm-1 measured in supersonic jets, which provide conditions relevant for astrophysics, are similar to those of most diffuse interstellar bands. The electronic transitions of BghiP are found to lie outside the ranges covered by present databases. From the comparison between experimental spectra and theoretical computations, it is concluded that the accuracy of empirical and ab initio approaches in predicting electronic energies is still not sufficient to identify astrophysically interesting candidates for spectroscopic laboratory studies.
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Affiliation(s)
- G Rouillé
- Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Helmholtzweg 3, D-07743 Jena, Germany
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Kokkin DL, Schmidt TW. On the Electronic Properties of Dehydrogenated Polycyclic Aromatic Hydrocarbons. J Phys Chem A 2006; 110:6173-7. [PMID: 16671689 DOI: 10.1021/jp057441v] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The electronic excited-state properties of a series of dehydrogenated polycyclic aromatic hydrocarbons from phenyl through to decacyl are reported. The radicals were investigated by use of time-dependent density functional theory in conjunction with the B3LYP functional. The pi and n orbitals were seen to converge in energy as the system increased in size, yet all radicals were found to have A' ground states. In addition to the study of the electronic state symmetries, the excited-state transitions and oscillator strengths were investigated with the resulting transitions found within the visible region of the spectrum, placing these radicals in the large group of candidate carriers of the diffuse interstellar bands.
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Affiliation(s)
- Damian L Kokkin
- School of Chemistry, University of Sydney, NSW 2006, Australia
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Electronic spectroscopy of polycyclic aromatic hydrocarbons (PAHs) at low temperature in the gas phase and in helium droplets. J Mol Struct 2006. [DOI: 10.1016/j.molstruc.2005.10.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Tan X, Salama F. Cavity ring-down spectroscopy and vibronic activity of benzo[ghi]perylene. J Chem Phys 2005; 123:014312. [PMID: 16035840 DOI: 10.1063/1.1938907] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Gas-phase cavity ring-down spectroscopy of jet-cooled benzo[ghi]perylene (C22H12) in the 26 950-28 600-cm(-1) spectral range is reported for the first time. This study is part of our extensive laboratory astrophysics program for the study of interstellar polycyclic aromatic hydrocarbons. The observed spectrum shows an intermediate level structure and significant broadening and is associated with the vibronically coupled S1(1A1)<--S0(1A1) and S2(1B1)<--S0(1A1) electronic transitions. Time-dependent density-functional calculations were performed to calculate the energetics, vibrational frequencies, and normal coordinates of the S1 and S2 states. A simple vibronic model was employed to account for the vibronic interaction between the vibronic levels of the S1 and S2 states. The calculated vibronic spectrum is found to be in good agreement with the experimental spectrum.
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Affiliation(s)
- Xiaofeng Tan
- Space Science Division, National Aeronautics and Space Administration (NASA) Ames Research Center, Mail Stop 245-6, Moffett Field, California 94035-1000, USA.
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Krasnokutski S, Rouillé G, Huisken F. Electronic spectroscopy of anthracene molecules trapped in helium nanodroplets. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.02.126] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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