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Bui TQ, Long DA, Cygan A, Sironneau VT, Hogan DW, Rupasinghe PM, Ciuryło R, Lisak D, Okumura M. Observations of Dicke narrowing and speed dependence in air-broadened CO₂ lineshapes near 2.06 μm. J Chem Phys 2015; 141:174301. [PMID: 25381508 DOI: 10.1063/1.4900502] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Frequency-stabilized cavity ring-down spectroscopy was used to study CO2 lineshapes in the (20013) ← (00001) band centered near 2.06 μm. Two rovibrational transitions were chosen for this study to measure non-Voigt collisional effects for air-broadened lines over the pressure range of 7 kPa-28 kPa. Lineshape analysis for both lines revealed evidence of simultaneous Dicke (collisional) narrowing and speed-dependent effects that would introduce biases exceeding 2% in the retrieved air-broadening parameters if not incorporated in the modeling of CO2 lineshapes. Additionally, correlations between velocity- and phase/state changing collisions greatly reduced the observed Dicke narrowing effect. As a result, it was concluded that the most appropriate line profile for modeling CO2 lineshapes near 2.06 μm was the correlated speed-dependent Nelkin-Ghatak profile, which includes all of the physical effects mentioned above and leads to a consistent set of line shape parameters that are linear with gas pressure.
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Affiliation(s)
- Thinh Q Bui
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - David A Long
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
| | - Agata Cygan
- Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland
| | - Vincent T Sironneau
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA
| | - Daniel W Hogan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Priyanka M Rupasinghe
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Roman Ciuryło
- Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland
| | - Daniel Lisak
- Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland
| | - Mitchio Okumura
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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Wcisło P, Tran H, Kassi S, Campargue A, Thibault F, Ciuryło R. Velocity-changing collisions in pure H2 and H2-Ar mixture. J Chem Phys 2014; 141:074301. [DOI: 10.1063/1.4892414] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Unified Impact Theory for Velocity-Changing Effects and Speed Dependencies in Neutral Species Lineshapes. ACTA ACUST UNITED AC 2010. [DOI: 10.1155/2010/306392] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A dipole correlation function which incorporates velocity-changing (motional narrowing) effects and the
effects of speed-dependent Lorentz relaxation rates into otherwise Voigt profile correlation functions is developed,
based partly upon previous work by the author. For the first time simple closed expressions, which lend themselves
to elementary calculation beginning only with the relevant parts of intermolecular interaction energies, are
developed for the cubic time-dependent term within the exponent describing the decay of the correlation function.
This term is of first order in perturber number density, as are the Lorentz parameters, and is complex, thereby
allowing for narrowing, changing in shape and asymmetry in the line profile. “Soft” and “hard” collisions play no explicit role, though both are variously present for each line. Quartic time dependencies are also discussed,
though they are thought to be negligible in nonhydrogen molecular spectroscopy. Finally, some comments are
added about a relevant technique for hydrogen spectra.
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Tran H, Chaussard F, Le Cong N, Lavorel B, Faucher O, Joubert P. Femtosecond time resolved coherent anti-Stokes Raman spectroscopy of H2–N2 mixtures in the Dicke regime: Experiments and modeling of velocity effects. J Chem Phys 2009; 131:174310. [DOI: 10.1063/1.3257640] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Tran H, Hartmann JM, Chaussard F, Gupta M. An isolated line-shape model based on the Keilson–Storer function for velocity changes. II. Molecular dynamics simulations and the Q(1) lines for pure H2. J Chem Phys 2009; 131:154303. [DOI: 10.1063/1.3247898] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Tran H, Hartmann JM. An isolated line-shape model based on the Keilson and Storer function for velocity changes. I. Theoretical approaches. J Chem Phys 2009; 130:094301. [DOI: 10.1063/1.3073758] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Tran H, Boulet C, Hartmann JM. Line mixing and collision-induced absorption by oxygen in the A band: Laboratory measurements, model, and tools for atmospheric spectra computations. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005jd006869] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Tran H, Joubert P, Bonamy L, Lavorel B, Renard V, Chaussard F, Faucher O, Sinardet B. Femtosecond time resolved coherent anti-Stokes Raman spectroscopy: experiment and modelization of speed memory effects on H2-N2 mixtures in the collision regime. J Chem Phys 2005; 122:194317. [PMID: 16161583 DOI: 10.1063/1.1894020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
With the aim of temperature diagnostic, femtosecond time-resolved CARS (coherent anti-Stokes Raman spectroscopy) is applied to probe H2 in H2-N2 mixtures. In a first part, a Lorentzian profile is used to model the femtosecond CARS response. A difference between the experimental broadening and the expected one is observed in the collision regime. The observed broadening increases strongly in an inhomogeneous way with respect to the perturber concentration. This is of considerable importance for temperature measurements. In a second part, we show that in the collision regime, this inhomogeneous broadening is due to the speed dependence of the collisional parameters and the memory effects of the radiator speed. A new modelization of the time-resolved CARS response taking into account the speed memory effects is presented and applied to the temperature diagnostic in H2-N2 mixtures. The numerical results are in good agreement with experiments.
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Affiliation(s)
- H Tran
- Laboratoire de Physique Moléculaire, UMR CNRS 6624, La Bouloie Université de Franche-Comté, 25030 Besançon Cedex, France and Laboratoire de Physique, UMR CNRS 5027, Université de Bourgogne, 21078 Dijon Cedex, France
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Joubert P, Bruet X, Bonamy J, Robert D, Chaussard F, Saint-Loup R, Berger H. Inhomogeneous speed effects on H2 vibrational line profiles in ternary mixtures. J Chem Phys 2000. [DOI: 10.1063/1.1322073] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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