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Stone D, Blitz M, Ingham T, Onel L, Medeiros DJ, Seakins PW. An instrument to measure fast gas phase radical kinetics at high temperatures and pressures. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:054102. [PMID: 27250442 DOI: 10.1063/1.4950906] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Fast radical reactions are central to the chemistry of planetary atmospheres and combustion systems. Laser-induced fluorescence is a highly sensitive and selective technique that can be used to monitor a number of radical species in kinetics experiments, but is typically limited to low pressure systems owing to quenching of fluorescent states at higher pressures. The design and characterisation of an instrument are reported using laser-induced fluorescence detection to monitor fast radical kinetics (up to 25 000 s(-1)) at high temperatures and pressures by sampling from a high pressure reaction region to a low pressure detection region. Kinetics have been characterised at temperatures reaching 740 K and pressures up to 2 atm, with expected maximum operational conditions of up to ∼900 K and ∼5 atm. The distance between the point of sampling from the high pressure region and the point of probing within the low pressure region is critical to the measurement of fast kinetics. The instrumentation described in this work can be applied to the measurement of kinetics relevant to atmospheric and combustion chemistry.
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Affiliation(s)
- Daniel Stone
- School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Mark Blitz
- School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Trevor Ingham
- School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Lavinia Onel
- School of Chemistry, University of Leeds, Leeds, United Kingdom
| | | | - Paul W Seakins
- School of Chemistry, University of Leeds, Leeds, United Kingdom
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2
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Marrocco M. Spatial laser-wing suppression in saturated laser-induced fluorescence without spatial selection. OPTICS LETTERS 2003; 28:2016-2018. [PMID: 14587800 DOI: 10.1364/ol.28.002016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Spatial wings of laser beams are of great concern in saturated laser-induced fluorescence. Their contribution to fluorescence is customarily avoided by resolution of laser peaks in the interaction volume. An alternative and versatile approach is formulated, based on the derivative of fluorescence with respect to laser intensity. It turns out that wing-free data are possible, although they are obtained from wing-dependent fluorescence. The advantages of this approach are exact centerline detection and simplicity of the experimental setup and procedure.
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Affiliation(s)
- Michele Marrocco
- Ente per le Nuove Tecnologie, l'Energia e l'Ambiente (ENEA)--Casaccia--Via Anguillarese 301, 00060 S. M. di Galeria, Rome, Italy.
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3
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Tobai J, Dreier T, Daily JW. Rotational level dependence of ground state recovery rates for OH X 2Π(v″=0) in atmospheric pressure flames using the picosecond saturating-pump degenerate four-wave mixing probe technique. J Chem Phys 2002. [DOI: 10.1063/1.1448284] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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4
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Kalemos A, Mavridis A, Metropoulos A. An accurate description of the ground and excited states of CH. J Chem Phys 1999. [DOI: 10.1063/1.480285] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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5
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Luque J, Crosley DR. Radiative, collisional, and predissociative effects in CH laser-induced-fluorescence flame thermometry. APPLIED OPTICS 1999; 38:1423-1433. [PMID: 18305763 DOI: 10.1364/ao.38.001423] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Laser-induced fluorescence of the CH radical is used to determine the flame-front temperature of an 8-Torr premixed CH(4)/O(2) flame. The A (2)D-X (2)Delta (0, 0) and B (2)Sigma- - X (2)II (0, 0) bands give values of 1960 +/- 60 and 1920 +/- 70 K, respectively. This is an improvement over a previous study that found discrepancies up to 20% between these bands. New rotational-level-dependent transition probabilities are the main reason for this improvement. The weaker off-diagonal bands A-X (0, 1) and B-X (0, 1) yield temperatures of 1930 +/- 90 and 1830 +/- 100 K, respectively. The influence of rotational transfer on the predissociated levels that have N' > in B (2)Sigma-, v'= 0 was investigated with fluorescence scans and a statistical power-gap law model of the relaxation; deviations up to 8% in temperature can occur because of this process.
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Affiliation(s)
- J Luque
- Molecular Physics Laboratory, SRI International, Menlo Park, California 94025, USA.
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6
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Kaminski CF, Hughes IG, Ewart P. Degenerate four-wave mixing spectroscopy and spectral simulation of C2 in an atmospheric pressure oxy-acetylene flame. J Chem Phys 1997. [DOI: 10.1063/1.473563] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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7
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Palmer JL, Hanson RK. Temperature imaging in a supersonic free jet of combustion gases with two-line OH fluorescence. APPLIED OPTICS 1996; 35:485-499. [PMID: 21069034 DOI: 10.1364/ao.35.000485] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Temperature measurements were performed in a shock-tunnel-generated free jet of hydrogen/oxygen reaction products diluted in argon with a nonsimultaneous, two-excitation-line planar laser-induced fluorescence technique with the hydroxyl radical (OH) as a tracer. Single-shot images were obtained with broadband excitation of isolated transitions in the A(2)Σ(+) ? X(2)Π(1, 0) band of OH near 282 nm, with broadband, temporally integrated detection of the resulting nonresonant emission. A measurement of the fluorescence lifetime in the free jet showed no variation with excited rotational level, allowing the rotational temperature to be obtained from the ratio of single-shot images with laser excitation of different rovibronic transitions.
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Desgroux P, Domingues E, Cottereau MJ. Measurements of OH concentration in flames at high pressure by two-optical path laser-induced fluorescence. APPLIED OPTICS 1992; 31:2831-2838. [PMID: 20725218 DOI: 10.1364/ao.31.002831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The two-optical path laser-induced fluorescence (TOPLIF) method was used to measure OH concentration profiles in flat, stoichiometric, premixed, methane-air flames burning at pressures ranging from 1 to 9 bars. The TOPLIF method does not require knowledge of the collisional quenching rates, which is a major advantage especially at these pressures. The population of a single rovibronic level is measured in a manner similar to many spectroscopic methods. TOPLIF measures this population at any location in flames at any pressure relative to this level's population in an arbitrary reference flame (here the 1-bar flame at 5 mm above the burner). Absolute values can therefore be obtained from the known value in the reference flame. In addition, the TOPLIF method is proposed as a technique to process standard laser-saturated fluorescence measurements. Using our approach, we can properly correct variations in the effective probe volume with pressure.
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9
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Carter CD, King GB, Laurendeau NM. Saturated fluorescence measurements of the hydroxyl radical in laminar high-pressure C(2)H(6)/O(2)/N(2) flames. APPLIED OPTICS 1992; 31:1511-1522. [PMID: 20720785 DOI: 10.1364/ao.31.001511] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We demonstrate saturation of a transition of the OH molecule in high-pressure flames by obtaining saturation curves in C(2)H(6)/O(2)/N(2) laminar flames at 1, 6.1, 9.2, and 12.3 atm. In addition we present quantitative fluorescence measurements of OH number density at pressures to 12.3 atm. To assess the efficacy of the balanced cross-rate model for high-pressure flames, we compare laser-saturated fluorescence measurements, which were calibrated in an atmospheric-pressure flame, with absorption measurements at 3.1 and 6.1 atm. At 3.1 atm the absorption and fluorescence measurements compare well. At 6.1 atm, however, the concentrations given by laser-saturated fluorescence are ~25% lower than the absorption values, indicating some depletion of the laser-coupled levels beyond that at atmospheric pressure. By using a reasonable estimate for the finite sensitivity to quenching, we anticipate that fluorescence measurements that are calibrated at 1 atm can be applied to flames at ~10 atm with absolute errors within +/-50%.
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10
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Zizak G, Petrucci GA, Stevenson CL, Winefordner JD. Ground state saturated population distribution of OH in an acetylene-air flame measured by two optical double resonance pump-probe approaches. APPLIED OPTICS 1991; 30:5270-5275. [PMID: 20717358 DOI: 10.1364/ao.30.005270] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Two optical double-resonance pump-probe techniques were used to determine the ground-state rotational population distributions of OH in an acetylene-air flame when a saturating laser beam is tuned to the Q(1)4 transition of the (0, 0) Sigma-II band. The saturated absorption technique is based on the detection of absorption by a probe laser under conditions of saturation with a pump laser and no saturation. In the fluorescence technique, a probe laser is scanned through the (1, 0) band, while a saturating pump laser, tuned to the (0, 0) band, is on or off. We found that approximately 15% of the total population of the ground state was transferred to the excited state. Perturbation of the rotational population distribution was greater for rotational levels close to the directly excited laser-coupled level. The rotational energy transfer rate in the ground state was somewhat greater than in the excited state. The assumption of the balanced cross-rate model was verified as a means of determining the absoslute OH number density with adequate accuracy.
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Desgroux P, Cottereau MJ. Local OH concentration measurement in atmospheric pressure flames by a laser-saturated fluorescence method: two-optical path laser-induced fluorescence. APPLIED OPTICS 1991; 30:90-97. [PMID: 20581952 DOI: 10.1364/ao.30.000090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The first (to our knowledge) measurements of number density of OH in flames at atmospheric pressure by TOPLIF are reported. TOPLIF (acronym for two optical paths laser-induced fluorescence) improves the accuracy of LIF measurements by taking into account both the spatial profile of the exciting laser intensity and the collisional transfer rate. The method is based on simultaneously recording the LIF signals from focal volumes of two different shapes. The ratio of the signals is a measure of the saturation parameter (which depends on the laser intensity and the quenching) using which accurate determination of the species number density can be deduced from the fluorescence signals. The method is valid as far as at least partial saturation is reached. First, experimental verification of the theoretical basis of the method is reported. The population of a single rovibronic level is measured as it is in most of the spectroscopic methods. TOPLIF measures this population relative to this level's population in a chosen reference flame. Absolute value can therefore be obtained if the value in the reference flame is known or measured. Absolute [OH] profiles obtained in flat flames burning at 60 and 1000 mb are presented and compared to laser absorption measurements.
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12
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Fleming JW, Burton KA, Ladouceur H. OH and CH profiles in a 10 Torr methane / oxygen flame: experiment and flame modeling. Chem Phys Lett 1990. [DOI: 10.1016/0009-2614(90)80131-v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Schwarzwald R, Monkhouse P, Wolfrum J. Fluorescence lifetimes for nitric oxide in atmospheric pressure flames using picosecond excitation. Chem Phys Lett 1989. [DOI: 10.1016/0009-2614(89)87293-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Rensberger KJ, Copeland RA, Wise ML, Crosley DR. NH and CH laser-induced fluorescence in low-pressure flames: Quantum yields from time-resolved measurements. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/s0082-0784(89)80201-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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15
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Rensberger KJ, Dyer MJ, Copeland RA. Time-resolved CH (A(2)Delta and B(2)Sigma(-)) laser-induced fluorescence in low pressure hydrocarbon flames. APPLIED OPTICS 1988; 27:3679-3689. [PMID: 20539441 DOI: 10.1364/ao.27.003679] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Total collisional removal rate constants for the CH A(2)Delta and B(2)Sigma(-) electronic states are obtained in low pressure (<20-Torr) hydrocarbon flames. The B state is consistently removed ~70% faster than the A state. Variations of +/-50% are observed for different rotational levels and positions in the flame. For these flames, A-state emission following excitation of the B state indicates a rapid electronic-to-electronic energy transfer pathway that is insensitive to collision environment. Upper limits to the collider specific cross sections are obtained for H(2)O, N(2), and CO(2). The CH concentration and temperature profiles are measured and parametrized using a unique method.
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16
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Tjossem PJ, Smyth KC. Multiphoton ionization detection of CH, carbon atoms, and O2 in premixed hydrocarbon flames. Chem Phys Lett 1988. [DOI: 10.1016/0009-2614(88)87088-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Garland NL, Crosley DR. On the collisional quenching of electronically excited OH, NH and CH in flames. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/s0082-0784(88)80402-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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18
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Carter CD, Salmon JT, King GB, Laurendeau NM. Feasibility of hydroxyl concentration measurements by laser-saturated fluorescence in high-pressure flames. APPLIED OPTICS 1987; 26:4551-4562. [PMID: 20523402 DOI: 10.1364/ao.26.004551] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A feasibility study has been performed on the application of laser-saturated fluoresence (LSF) to the measurement of OH concentration in high-pressure flames. Using a numerical model for the collisional dynamics of the OH molecule under nonuniform laser excitation, we have investigated the effect of pressure on the balanced cross-rate model and determined the sensitivity of the depopulation of the laser-coupled levels to the ratio of rate coefficients describing (1) electronic quenching of the vibrational levels for which upsilon'' > 0 and (2) vibrational relaxation from upsilon'' > 0 to upsilon'' = 0. At sufficiently high pressures in near-saturated conditions, the total population of the laser-coupled levels reaches an asymptotic value, which is insensitive to the degree of saturation. When the ratio of electronic quenching is vibrational relaxation is small and the rate coefficients for rotational transfer in the ground and excited electronic states are nearly the same, the balanced cross-rate model remains a good approximation for all pressures. When the above ratio is large, depopulation of the laser-coupled levels becomes significant at high pressures, and thus the balanced crossrate model no longer holds. In these conditions, however, knowledge of the asymptotic value achieved by the laser-coupled levels could be used to correct the balanced cross-rate model and thus allow LSF measurements at sufficiently high pressures.
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Zizak G, Cignoli F, Benecchi S. Spatially resolved saturated absorption measurements of OH in methane-air flames. APPLIED OPTICS 1987; 26:4293-4297. [PMID: 20490224 DOI: 10.1364/ao.26.004293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A cross-beam saturated absorption spectroscopy technique, utilizing a single pulsed dye laser, has been developed for local concentration measurements in flames. With a differential detection of the probe and the reference laser beam intensities, a significant improvement of the technique has been achieved. In this work the basic theory of the method is discussed. Its use in combustion studies is demonstrated by presenting OH concentration profiles in two premixed laminar methane-air flames.
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20
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Greenblatt G, Zuckermann H, Haas Y. OH production in the collision-free UV photolysis of aliphatic nitro compounds. Chem Phys Lett 1987. [DOI: 10.1016/0009-2614(87)87200-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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21
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Kohse-Höinghaus K, Kelm S, Meier U, Bittner J, Just T. Concentration Profiles of Flame Radicals Determined by Laser-Induced Fluorescence. ACTA ACUST UNITED AC 1987. [DOI: 10.1007/978-3-642-83224-6_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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22
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Cottereau MJ. Single-shot laser-saturated fluorescence measurements: a new method. APPLIED OPTICS 1986; 25:744-748. [PMID: 18231244 DOI: 10.1364/ao.25.000744] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A new method of laser-saturated fluorescence shot-to-shot concentration measurement is proposed. The method is based on use of the wing effect of a nonuniform laser irradiance. The measurement is independent of both the collisional transfer rate and variation in laser power. If the laser power is known it is also a method of measurement of the collisional transfer rate at any pressure.
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Affiliation(s)
- M J Cottereau
- Universite de Rouen, Laboratoire de Thermodynamique U.A. CNRS 230, B.P. 67, 76130 Mont-Saint-Aignan, France
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Garland NL, Crosley DR. Energy transfer processes in CH A2Delta and B2Sigma- in an atmospheric pressure flame. APPLIED OPTICS 1985; 24:4229. [PMID: 18224190 DOI: 10.1364/ao.24.004229] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Salmon JT, Laurendeau NM. Analysis of probe volume effects associated with laser-saturated fluorescence measurements. APPLIED OPTICS 1985; 24:1313. [PMID: 18223712 DOI: 10.1364/ao.24.001313] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Salmon JT, Laurendeau NM. Calibration of laser-saturated fluorescence measurements using Rayleigh scattering. APPLIED OPTICS 1985; 24:65-73. [PMID: 18216906 DOI: 10.1364/ao.24.000065] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Calibration of laser-saturated fluorescence measurements using Rayleigh scattering is presented as an alternative to absorption. This new procedure is advantageous when measuring radical species at concentrations well below the corresponding detection limit for absorption. The calibration accounts for nonuniform laser irradiation by extracting the local fluorescence emission along the laser axis and works equally well for both saturated and near-saturated center-line conditions. The predicted error due to misfocusing of the collection optics is nearly negligible when the measured fluorescence is within 10% of its peak value. Number densities obtained using this method are within 15% of those obtained from absorption measurements.
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Affiliation(s)
- J T Salmon
- Purdue University, School of Mechanical Engineering, Flame Diagnostics Laboratory, West Lafayette, Indiana 47907, USA
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Kohse-Höinghaus K, Heidenreich R, Just T. Determination of absolute OH and CH concentrations in a low pressure flame by laser-induced saturated fluorescence. ACTA ACUST UNITED AC 1985. [DOI: 10.1016/s0082-0784(85)80606-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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