Linewidth modelling of C2H2N2 mixtures tested by rotational CARS measurements

Buldyreva, J.; Bonamy, J.; Weikl, Markus C.; Beyrau, Frank; Seeger, Thomas; Leipertz, Alfred; Vestin, Fredrik; Afzelius, Mikael; Bood, Joakim; Bengtsson, Per-Erik

doi:10.1002/jrs.1491

Cited by 39 publications

(23 citation statements)

References 23 publications

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“…In addition the detection of other major species e.g. [131] has been reported. Since neither the pump nor the Stokes frequencies correspond to allowed single photon transitions the excitation is achieved via a two-photon process.…”

Section: Coherent Anti-stokes Raman Scatteringmentioning

confidence: 98%

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Kiefer

Ewart

2011

Progress in Energy and Combustion Science

131

112

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Laser-based methods have transformed combustion diagnostics in the past few decades. The high intensity, coherence, high spectral resolution and frequency tunability available from laser radiation has provided powerful tools for studying microscopic processes and macroscopic phenomena in combustion by linear and nonlinear optical processes. This review focuses on nonlinear optical techniques based on resonant four-wave mixing for non-intrusive measurements of minor species in combustion. The importance of minor species such as reaction intermediates is outlined together with the challenges they present for detection and measurement in the hostile environments of flames, technical combustors, and engines. The limitations of conventional optical methods for such measurements are described and the particular advantages of coherent methods using nonlinear optical techniques are discussed.The basic physics underlying four-wave wave mixing processes and theoretical models for signal calculation are then presented together with a discussion of how combustion parameters may be derived from analysis of signals generated in various four-wave mixing processes. The most important four-wave mixing processes, in this context, are then reviewed:Degenerate Four-Wave Mixing (DFWM), Coherent Anti-Stokes Raman Scattering (CARS), Laser Induced Grating Spectroscopy (LIGS) and Polarization Spectroscopy (PS). In each case the fundamental physics is outlined to explain the particular properties and diagnostic advantages of each technique. The application of the methods mentioned to molecular physics studies of combustion species is then reviewed along with their application in measurement of concentration, temperature and other combustion parameters. Related nonlinear techniques and recent extensions to the ultra-fast regime are briefly reviewed. Finally practical considerations relevant to multi-dimensional and multi-species measurements, as well as applications in technical combustion systems are discussed.Keywords: nonlinear optical spectroscopy, four-wave mixing, combustion diagnostics, minor species detection, laser-induced gratings, polarization spectroscopy IntroductionEnergy from renewable sources such as solar and wind power is the goal of much current research and technological development. Combustion, however, is and is likely to remain for the foreseeable future, the most important energy source for heat, electrical power and especially for transportation. In technical combustion systems the chemical energy of fossil fuels such as coal, crude oil and natural gas is converted into heat through oxidation with oxygen from air. However, fossil fuel resources are limited and alternatives like biofuels [1] or novel technologies such as fuel cells [2] are not yet able to meet the demand. Consequently, for a sustainable use of fossil fuels it is desirable to further improve the efficiency, maintainability and reliability of existing combustion devices. Achieving such improvements depends upon an improved understanding of t...

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Section: Coherent Anti-stokes Raman Scatteringmentioning

confidence: 98%

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Kiefer

Ewart

2011

Progress in Energy and Combustion Science

131

112

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“…(3) up to L 1 ¼L 2 ¼4 (see for instance Refs. [11,[18][19][20]22] and references therein). We have checked that higher multipolar components of the PES do not provide any significant contributions to such calculations of the pressure broadening coefficients.…”

Section: Semi-classical Robert-bonamy Methodsmentioning

confidence: 99%

“…Due to the interest of the C 2 H 2 -N 2 system many theoretical calculations of the nitrogen broadening of acetylene lines have also been performed [1,3,4,[8][9][10][11]. However, these calculations were almost all conducted with the semi-classical method of Robert and Bonamy [12] using semi-empirical potentials.…”

mentioning

confidence: 99%

An experimental and theoretical study of nitrogen-broadened acetylene lines

Thibault

Martínez

Bermejo

et al. 2014

Journal of Quantitative Spectroscopy and Radiative Transfer

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a b s t r a c tWe present experimental nitrogen-broadening coefficients derived from Voigt profiles of isotropic Raman Q-lines measured in the ν 2 band of acetylene (C 2 H 2 ) at 150 K and 298 K, and compare them to theoretical values obtained through calculations that were carried out specifically for this work. Namely, full classical calculations based on Gordon's approach, two kinds of semi-classical calculations based on Robert-Bonamy method as well as full quantum dynamical calculations were performed. All the computations employed exactly the same ab initio potential energy surface for the C 2 H 2 -N 2 system which is, to our knowledge, the most realistic, accurate and up-to-date one. The resulting calculated collisional half-widths are in good agreement with the experimental ones only for the full classical and quantum dynamical methods. In addition, we have performed similar calculations for IR absorption lines and compared the results to bibliographic values. Results obtained with the full classical method are again in good agreement with the available room temperature experimental data. The quantum dynamical closecoupling calculations are too time consuming to provide a complete set of values and therefore have been performed only for the R(0) line of C 2 H 2 . The broadening coefficient obtained for this line at 173 K and 297 K also compares quite well with the available experimental data. The traditional Robert-Bonamy semi-classical formalism, however, strongly overestimates the values of half-width for both Q-and R-lines. The refined semiclassical Robert-Bonamy method, first proposed for the calculations of pressure broadening coefficients of isotropic Raman lines, is also used for IR lines. By using this improved model that takes into account effects from line coupling, the calculated semi-classical widths are significantly reduced and closer to the measured ones.

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“…7 In view of the importance of the C 2 H 2 molecule, several recent experimental and theoretical works have been devoted to the determination of Raman linewidths. [8][9][10][11] Vereschagin et al reported the self-broadening coefficients of ν 2 Q-branch odd-J lines from 7 to 15, determined using vibrational CARS spectroscopy. 10 Domenech et al reported measurements of Ar-broadening coefficients associated with the same vibrational manifold at different temperatures using high-resolution stimulated Raman spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Direct measurements of collisional Raman line broadening in the S-branch transitions of acetylene (C2H2)

Hsu

Stauffer

Jiang

et al. 2013

The Journal of Chemical Physics

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We report direct measurements of the self- and N2-broadened Raman S-branch linewidths of acetylene (C2H2), obtained by employing time-resolved picosecond rotational coherent anti-Stokes Raman scattering spectroscopy. Using broadband 115-ps pump and Stokes pulses (~135 cm(-1) bandwidth) and a spectrally narrowed 90-ps probe pulse (~0.2 cm(-1) bandwidth), Raman-coherence lifetimes are measured at room temperature for the S-branch (ΔJ = +2) transitions associated with rotational quantum number J = 3-25. These directly measured Raman-coherence lifetimes, when converted to collisional linewidth broadening coefficients, differ from the previously reported broadening coefficients extracted from theoretical calculations by 6%-35% for self-broadening for C2H2 and by up to 60% for N2-broadened C2H2.

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Linewidth modelling of C₂H₂N₂ mixtures tested by rotational CARS measurements

Cited by 39 publications

References 23 publications

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

An experimental and theoretical study of nitrogen-broadened acetylene lines

Direct measurements of collisional Raman line broadening in the S-branch transitions of acetylene (C2H2)

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