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Orr BJ. Collision-induced rovibrational energy transfer in small polyatomic molecules: the role of intramolecular perturbations. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1490463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Brian J. Orr
- Department of Physics and Astronomy, MQ Photonics Research Centre, Macquarie University, Sydney, Australia
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2
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Lane RA, Madden TJ. Numerical investigation of pulsed gas amplifiers operating in hollow-core optical fibers. OPTICS EXPRESS 2018; 26:15693-15704. [PMID: 30114827 DOI: 10.1364/oe.26.015693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/27/2018] [Indexed: 06/08/2023]
Abstract
Optically pumped molecular gas amplifiers having a gain medium contained in a hollow-core optical fiber are investigated with numerical modeling to understand the primary physical processes that affect amplifier output and efficiency. A comparison of computational results with experimental measurements of incident pump, absorbed pump, and emitted mid-IR from a pulsed, acetylene-filled, hollow-core fiber amplifier [ Opt. Exp.25, 13351 (2017)] is used to explore the effects of various physical processes on pulsed amplifier operation. Single frequency, one-dimensional, time-dependent models are shown to align with experimentally measured lasing thresholds and ratios of absorbed pump to emitted laser energy but significantly over predict the amount of incident pump energy that is absorbed. A two-dimensional, time-dependent model that assumes Gaussian spectral and radial intensity profiles for the pump is developed and shows an improved ability to capture pump absorption. Results indicate that 1D, time-dependent models have utility in guiding experiments but the significant influence of the pump and laser propagation modes and the pump spectral characteristics on efficiency, threshold, and signal output must be explicitly included in high-fidelity high-power modeling.
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3
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Santos L, Herman M, Desouter-Lecomte M, Vaeck N. Rovibrational laser control targeting a dark state in acetylene. Simulation in the Ns = 1, Nr = 5 polyad. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1469797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- L. Santos
- Service de Chimie quantique et Photophysique, Université libre de Bruxelles, Brussels, Belgium
| | - M. Herman
- Service de Chimie quantique et Photophysique, Université libre de Bruxelles, Brussels, Belgium
| | - M. Desouter-Lecomte
- Laboratoire de Chimie Physique, Université Paris-sud, Orsay, France
- Département de Chimie, Université de Liége, Liége, Belgium
| | - N. Vaeck
- Service de Chimie quantique et Photophysique, Université libre de Bruxelles, Brussels, Belgium
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Liu AW, Li XF, Wang J, Lu Y, Cheng CF, Sun YR, Hu SM. The 4ν(CH) overtone of 12C2H2: sub-MHz precision spectrum reveals perturbations. J Chem Phys 2013; 138:014312. [PMID: 23298046 DOI: 10.1063/1.4773473] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The third CH stretching vibration overtone (4ν(CH)) of the acetylene molecule has been a prototype for intra-molecular dynamics studies. Using a sensitive cavity ring-down spectrometer calibrated with precise atomic transitions, the absolute line frequencies of 50 lines of this band have been determined with sub-MHz accuracy, or relatively 2 × 10(-9). The accuracy is also confirmed by the combination differences between the transitions sharing the same upper level. The improved accuracy, two orders of magnitude better than previous studies, allows us to reveal finer ro-vibrational couplings. Fitting of the rotational energies indicates that the J-dependent interactions take place after J > 7. The precise line positions present useful confinements to the models of the intra-molecular interactions of the acetylene molecule.
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Affiliation(s)
- A-W Liu
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China
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5
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Han J, Freel K, Heaven MC. Rotational and vibrational energy transfer in vibrationally excited acetylene at energies near 6560 cm−1. J Chem Phys 2011; 135:244304. [DOI: 10.1063/1.3671459] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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6
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Orr BJ. Spectroscopy and energetics of the acetylene molecule: dynamical complexity alongside structural simplicity. INT REV PHYS CHEM 2010. [DOI: 10.1080/01442350600892577] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Brian J. Orr
- a Department of Physics and Centre for Lasers and Applications , Macquarie University , Sydney , NSW 2109 , Australia
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Abstract
Abstract
H and D photofragments, produced via vibrationally mediated photodissociation of jet-cooled C2HD allowed measurement of vibrational and vibronic excitation action spectra of the parent as well as H and D Doppler profiles. The initial vibrational preparation at energies around 9700 cm−1 enhanced C—H and C—D bond cleavage for transitions from an initially excited bent state to the upper A
~ state, rather than from a close lying state containing three C—H stretch quanta, due to favorable Franck—Condon factors for the former. The bound region of the A
~ state was accessed, resulting in non-adiabatic dissociation and slight preferential C—H over C—D bond cleavage.
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Payne MA, Milce AP, Frost MJ, Orr BJ. Rovibrational Energy Transfer in the 4νCH Manifold of Acetylene, Viewed by IR-UV Double Resonance Spectroscopy. 3. State-to-State J-Resolved Kinetics. ACTA ACUST UNITED AC 2009. [DOI: 10.1524/zpch.219.5.601.64327] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Time-resolved infrared-ultraviolet double resonance (IR-UV DR) spectroscopy is used to study the kinetics of collision-induced state-to-state molecular energy transfer between rovibrational states in the 12700-cm−1 4νCH manifold of the electronic ground state of acetylene (C2H2). Particular initial and final rovibrational J-states are prepared and monitored by a pair of tunable laser pulses (IR PUMP and UV PROBE) and the kinetic results recorded by continuously varying the time delay between those pulses at a set sample pressure. After allowing for collision-induced quenching of fluorescence and mass transfer from the IR-UV optical excitation zone (by beam flyout and diffusion), an array of kinetic data for J-resolved energy-transfer channels can be interpreted by means of a mechanistically structured master-equation model. This paper focuses on kinetics derived by probing C2H2 in its 4νCH
J = 12 state (which is affected by intramolecular perturbations and implicated in unusual collision-induced quasi-continuous background effects) and J-resolved collision-induced rovibrational energy transfer with both even ΔJ and (supposedly forbidden) odd ΔJ.
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Amyay B, Robert S, Herman M, Fayt A, Raghavendra B, Moudens A, Thiévin J, Rowe B, Georges R. Vibration-rotation pattern in acetylene. II. Introduction of Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 μm. J Chem Phys 2009; 131:114301. [DOI: 10.1063/1.3200928] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Payne MA, Milce AP, Frost MJ, Orr BJ. Rovibrational Energy Transfer in the 4νCH Manifold of Acetylene, Viewed by IR−UV Double Resonance Spectroscopy. 5. Detailed Kinetic Model. J Phys Chem A 2007; 111:12839-53. [DOI: 10.1021/jp0767617] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mark A. Payne
- Centre for Lasers and Applications, Macquarie University, Sydney, NSW 2109, Australia
| | - Angela P. Milce
- Centre for Lasers and Applications, Macquarie University, Sydney, NSW 2109, Australia
| | - Michael J. Frost
- Centre for Lasers and Applications, Macquarie University, Sydney, NSW 2109, Australia
| | - Brian J. Orr
- Centre for Lasers and Applications, Macquarie University, Sydney, NSW 2109, Australia
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Payne MA, Milce AP, Frost MJ, Orr BJ. Rovibrational Energy Transfer in the 4νCH Manifold of Acetylene, Viewed by IR−UV Double-Resonance Spectroscopy. 4. Collision-Induced Quasi-Continuous Background Effects. J Phys Chem A 2006; 110:3307-19. [PMID: 16509657 DOI: 10.1021/jp055245i] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The 4nu(CH) rovibrational manifold around 12 700 cm(-1) in the electronic ground state, X, of acetylene (C2H2) is monitored by time-resolved infrared-ultraviolet double-resonance (IR-UV DR) spectroscopy. An IR laser pulse initially prepares rotational J states, associated with the "IR-bright" (nu1 + 3nu3) or (1 0 3 0 0)0 vibrational combination level, and subsequent collision-induced state-to-state energy transfer is probed by UV laser-induced fluorescence. Anharmonic, l-resonance, and Coriolis couplings affect the J states of interest, resulting in a congested rovibrational manifold that exhibits complex intramolecular dynamics. In preceding papers in this series, we have described three complementary forms of the IR-UV DR experiment (IR-scanned, UV-scanned, and kinetic) on collision-induced rovibrational satellites, comprising both regular even-DeltaJ features and unexpected odd-DeltaJ features. This paper examines an unusual collision-induced quasi-continuous background (CIQCB) effect that is apparently ubiquitous, accompanying regular even-DeltaJ rovibrational energy transfer and accounting for much of the observed collision-induced odd-DeltaJ satellite structure; certain IR-bright (1 0 3 0 0)0 rovibrational states (e.g., J = 12) are particularly prominent in this regard. We examine the mechanism of this CIQCB phenomenon in terms of a congested IR-dark rovibrational manifold that is populated by collisional transfer from the nearly isoenergetic IR-bright (1 0 3 0 0)0 submanifold.
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Affiliation(s)
- Mark A Payne
- Centre for Lasers and Applications, Macquarie University, Sydney, NSW 2109, Australia
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12
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Payne MA, Milce AP, Frost MJ, Orr BJ. Rovibrational Energy Transfer in the 4νCH Manifold of Acetylene Viewed by IR−UV Double Resonance Spectroscopy. 2. Perturbed States with J = 17 and 18. J Phys Chem B 2005; 109:8332-43. [PMID: 16851977 DOI: 10.1021/jp0463518] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Collision-induced state-to-state molecular energy transfer between rovibrational states in the 12,700 cm(-1) 4nu(CH) manifold of the electronic ground state X of acetylene (C(2)H(2)) is monitored by time-resolved infrared-ultraviolet double resonance (IR-UV DR) spectroscopy. Rotational J-states associated with the (nu(1) + 3nu(3)) or (1 0 3 0 0)(0) vibrational combination level, initially prepared by an IR pulse, are probed at approximately 299, approximately 296, or approximately 323 nm with UV laser-induced fluorescence via the Alpha electronic state. The rovibrational J-states of interest belong to a congested manifold that is affected by anharmonic, l-resonance, and Coriolis couplings, yielding complex intramolecular dynamics. Consequently, collision-induced rovibrational satellites observed by IR-UV DR comprise not only regular even-DeltaJ features but also supposedly forbidden odd-DeltaJ features. A preceding paper (J. Phys. Chem. A 2003, 107, 10759) focused on low-J-value rovibrational levels of the 4nu(CH) manifold (particularly those with J = 0 and J = 1) whereas this paper examines locally perturbed states at higher values of J (particularly J = 17 and 18, which display anomalous doublet structure in IR-absorption spectra). Three complementary forms of IR-UV DR experiments (IR-scanned, UV-scanned, and kinetic) are used to address the extent to which intramolecular perturbations influence the efficiency of J-resolved collision-induced energy transfer with both even and odd DeltaJ.
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Affiliation(s)
- Mark A Payne
- Centre for Lasers and Applications, Macquarie University, Sydney, New South Wales 2109, Australia
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