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Murray JS, Clemens NT. Two-photon laser-induced fluorescence study of the CO B 1Σ+ (v' = 0) state in a 4850 K plasma plume: Modified molecular constants, evidence of predissociation, and J'-dependent photoionization. J Chem Phys 2024; 160:244302. [PMID: 38912626 DOI: 10.1063/5.0207622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 06/04/2024] [Indexed: 06/25/2024] Open
Abstract
We report the two-photon absorption laser-induced fluorescence rotational spectrum of the CO B 1Σ+ ← X 1Σ+ Hopfield-Birge system (v' = 0, v″ = 0) Q-branch in an ∼4850 K, atmospheric pressure plasma torch plume at thermal equilibrium in both the quenching-dominated (low laser intensity) and photoionization-dominated (high laser intensity) regimes. We provide a detailed analysis of the photophysics in these two regimes using a rate equation approach and propose modeling considerations for them as well. In the experimental spectra, distinct rotational transitions up to J″ = 83 are observed, allowing analysis over a very large range of rotational states. Evidence of predissociation is observed for J' ≥ 64 and is likely due to the interaction with the D'1Σ+ electronic state, which has been proposed in the literature but never observed in the v' = 0 state. The line positions of higher rotational states show disagreement with line positions calculated from molecular constants in the available literature, suggesting the need for modifications to the constants, which are reported here. A shift in the B 1Σ+ ← X 1Σ+ absorption spectrum toward higher two-photon energy as a result of the second-order Stark shift was observed in the photoionization-dominated spectrum, and the second-order Stark shift cross section was estimated to be 7 ± 3 × 10-18 cm2. The mean photoionization cross section of the excited upper state was inferred by comparing the line broadening of the two spectra and was estimated to be 11 ± 7 × 10-18 cm2. In addition, weak J'-dependent variations of the photoionization cross section were observed and are reported here.
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Affiliation(s)
- John S Murray
- Department of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Noel T Clemens
- Department of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin, Austin, Texas 78712, USA
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Abplanalp MJ, Frigge R, Kaiser RI. Low-temperature synthesis of polycyclic aromatic hydrocarbons in Titan's surface ices and on airless bodies. SCIENCE ADVANCES 2019; 5:eaaw5841. [PMID: 31663015 PMCID: PMC6795510 DOI: 10.1126/sciadv.aaw5841] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 09/22/2019] [Indexed: 06/10/2023]
Abstract
Titan's equatorial dunes represent the most monumental surface structures in our Solar System, but the chemical composition of their dark organics remains a fundamental, unsolved enigma, with solid acetylene detected near the dunes implicated as a key feedstock. Here, we reveal in laboratory simulation experiments that aromatics such as benzene, naphthalene, and phenanthrene-prospective building blocks of the organic dune material-can be efficiently synthesized via galactic cosmic ray exposure of low-temperature acetylene ices on Titan's surface, hence challenging conventional wisdom that aromatic hydrocarbons are formed solely in Titan's atmosphere. These processes are also of critical importance in unraveling the origin and chemical composition of the dark surfaces of airless bodies in the outer Solar System, where hydrocarbon precipitation from the atmosphere cannot occur. This finding notably advances our understanding of the distribution of carbon throughout our Solar System such as on Kuiper belt objects like Makemake.
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Affiliation(s)
- Matthew J. Abplanalp
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Robert Frigge
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Ralf I. Kaiser
- W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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Sun ZF, Scheidsbach RJA, Suits AG, Parker DH. Imaging multiphoton ionization and dissociation of rotationally warm CO via the B +Σ 1 and EΠ1 electronic states. J Chem Phys 2017; 147:013906. [PMID: 28688406 DOI: 10.1063/1.4973677] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Pathways for formation of C+ and O+ ions when applying (2 + 1) resonance enhanced multiphoton ionization (REMPI) of CO via the B1Σ+ and E1Π electronic states are characterized with the velocity map imaging technique. By employing an unskimmed pulsed valve, it was possible to obtain sharp images for a wide range of initial CO J-states. Most of the atomic ion production pathways could be assigned as one- or two-photon dissociation of a series of vibrational levels of the CO+ X2Σ+ and A2Π states. Large enhancements in dissociation of particular CO+ vibrational states in these progressions could be accurately assigned to accidental resonances of the REMPI laser with CO+ X2Σ+-B2Σ+ transitions.
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Affiliation(s)
- Z-F Sun
- Department of Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - R J A Scheidsbach
- Department of Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - A G Suits
- Chemistry Department, University of Missouri, 125 Chemistry Building, Columbia, Missouri 65211, USA
| | - D H Parker
- Department of Molecular and Laser Physics, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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Liu HT, Huang DL, Liu Y, Cheung LF, Dau PD, Ning CG, Wang LS. Vibrational State-Selective Resonant Two-Photon Photoelectron Spectroscopy of AuS(-) via a Spin-Forbidden Excited State. J Phys Chem Lett 2015; 6:637-642. [PMID: 26262479 DOI: 10.1021/acs.jpclett.5b00053] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Vibrational state-selective resonant two-photon photoelectron spectra have been obtained via a triplet intermediate state ((3)Σ(-)) of AuS(-) near its detachment threshold using high-resolution photoelectron imaging of cryogenically cooled AuS(-) anions. Four vibrational levels of the (3)Σ(-) excited state are observed to be below the detachment threshold. Resonant two-photon absorptions through these levels yield vibrational state-selective photoelectron spectra to the (2)Σ final state of neutral AuS with broad and drastically different Franck-Condon distributions, reflecting the symmetries of the vibrational wave functions of the (3)Σ(-) intermediate state. The (3)Σ(-) excited state is spin-forbidden from the (1)Σ(+) ground state of AuS(-) and is accessed due to strong relativistic effects. The nature of the (3)Σ(-) excited state is confirmed by angular distributions of the photoelectron images and quantum calculations.
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Affiliation(s)
- Hong-Tao Liu
- †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
- ‡Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Dao-Ling Huang
- †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Yuan Liu
- §Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Ling-Fung Cheung
- §Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Phuong Diem Dau
- †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Chuan-Gang Ning
- §Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
| | - Lai-Sheng Wang
- †Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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Hakalla R, Zachwieja M, Szajna W. First analysis of the 1-v″ progression of the Ångström (B1Σ+-A1Π) band system in the rare 13C17O isotopologue. J Phys Chem A 2013; 117:12299-312. [PMID: 24138166 DOI: 10.1021/jp4077239] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The 1-v″ progression of the Ångström band system, so far unobserved in the rare (13)C(17)O isotopologue, was obtained under high resolution as an emission spectrum using a high accuracy dispersive optical spectroscopy. In the studied region 22,700-24,500 cm(-1), 146 spectral lines were observed, among which 118 were interpreted as belonging to the 1-0 and 1-1 bands of B-A system, and the next 28 were interpreted as extra lines belonging to the 1-1 band of B(1)Σ(+)-e(3)Σ(-) intercombination system, also unobserved in the (13)C(17)O molecule so far. All those lines were precisely measured with an estimated accuracy better than 0.0025 cm(-1), and rotationally analyzed. As a result the following in the (13)C(17)O molecule were calculated for the first time: the merged rotational constants B1 = 1.790227(23) cm(-1), D1 = 6.233(47) × 10(-6) cm(-1), and ΔG1/2 = 2010.9622 (69) cm(-1) and the equilibrium constants, ωe = 2076.04(57) cm(-1), ωexe = 32.54(28) cm(-1), Be = 1.824678(15) cm(-1), αe = 2.2967(24) × 10(-2) cm(-1), De = 5.226(25) × 10(-6) cm(-1), and βe = 6.71(48) × 10(-7) cm(-1) for the B(1)Σ(+) Rydberg state, as well as the individual rotational constant B0 = 1.50485(78) cm(-1), and the equilibrium constants ωe = 1463.340(21) cm(-1), Be = 1.49902(12) cm(-1), αe = 1.7782(49) × 10(-2) cm(-1), De = 7.36(56) × 10(-6) cm(-1) for the A(1)Π state, and σe = 21,854.015(51) cm(-1), RKR turning points, Franck-Condon factors (FCF), relative intensities, and r centroids for the Ångström band system. With the help of the strong and vast A(1)Π (v = 0) ∼ e(3)Σ(-) (v = 1) interaction, the experimental parameters of the e(3)Σ(-) (v = 1) perturbing state were established in the (13)C(17)O molecule for the first time.
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Affiliation(s)
- Rafał Hakalla
- Materials Spectroscopy Laboratory, Center for Innovation and Transfer of Engineering and Natural Science Knowledge, University of Rzeszów , 35-959 Rzeszów, Poland
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Shen L, Zhang B, Suits AG. Photoelectron Imaging and (2 + 1) Resonance Enhanced Multiphoton Ionization Spectroscopy Study of 2-Butanone Photoionization Dynamics. J Phys Chem A 2010; 114:3114-20. [DOI: 10.1021/jp908491w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lei Shen
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202
| | - Bailin Zhang
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202
| | - Arthur G. Suits
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202
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Romanescu C, Loock HP. Photoelectron imaging following 2 + 1 multiphoton excitation of HBr. Phys Chem Chem Phys 2006; 8:2940-9. [PMID: 16880906 DOI: 10.1039/b602435a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photodissociation and photoionization dynamics of HBr via low-n Rydberg and ion-pair states was studied by using 2 + 1 REMPI spectroscopy and velocity map imaging of photoelectrons. Two-photon excitation at about 9.4-10 eV was used to prepare rotationally selected excited states. Following absorption of the third photon the unperturbed F (1)Delta(2) and i (3)Delta(2) states ionize directly into the ground vibrational state of the molecular ion according to the Franck-Condon principle and upon preservation of the ion core. In case of the V (1)Sigma(+)(0(+)) ion-pair state and the perturbed E (1)Sigma(+)(0(+)), g (3)Sigma(-)(0(+)), and H (1)Sigma(+)(0(+)) Rydberg states the absorption of the third photon additionally results in a long vibrational progression of HBr(+) in the X (2)Pi state as well as formation of electronically excited atomic photofragments. The vibrational excitation of the molecular ion is explained by autoionization of repulsive superexcited states into the ground state of the molecular ion. In contrast to HCl, the perturbed Rydberg states of HBr show strong participation of the direct ionization process, with ionic core preservation.
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Affiliation(s)
- Constantin Romanescu
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Canada ON K7L 3N6
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Li W, Lahankar SA, Huang C, Shternin PS, Vasyutinskii OS, Suits AG. Multiphoton processes of CO at 230 nm. Phys Chem Chem Phys 2006; 8:2950-7. [PMID: 16880907 DOI: 10.1039/b603870k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High resolution kinetic energy release spectra were obtained for C(+) and O(+) from CO multiphoton ionization followed by dissociation of CO(+). The excitation was through the CO (B (1)Sigma(+)) state via resonant two-photon excitation around 230 nm. A total of 5 and 6 photons are found to contribute to the production of carbon and oxygen cations. DC slice and Megapixel ion imaging techniques were used to acquire high quality images. Major features in both O(+) and C(+) spectra are assigned to the dissociation of some specific vibrational levels of CO(+)(X (2)Sigma(+)). The angular distributions of C(+) and O(+) are very distinct and those of various features of C(+) are also different. A dramatic change of the angular distribution of C(+) from dissociation of CO(+)(X (2)Sigma(+), nu(+) = 1) is attributed to an accidental one-photon resonance between CO(+)(X (2)Sigma(+), nu(+) = 1) and CO(+)(B (2)Sigma(+), nu(+) = 0) and explained well by a theoretical model. Both kinetic energy release and angular distributions were used to reveal the underlying dynamics.
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Affiliation(s)
- Wen Li
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA
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Tsubouchi M, de Lange CA, Suzuki T. Femtosecond time-resolved charged particle imaging studies of the ultraviolet photodissociation of the NO dimer. J Chem Phys 2003. [DOI: 10.1063/1.1624600] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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