Temperature Dependence of O + OH at 136−377 K Using Ozone Photolysis

Robertson, Robert; Smith, Gregory P.

doi:10.1021/jp055863z

Cited by 24 publications

(18 citation statements)

References 26 publications

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“…As a consequence, the HO 2 system has been the topic of numerous electronic structure calculations of its potential energy surface [10,11,12,13,14,15] as well as dynamics calculations to evaluate its temperature dependent rate coefficients [13,14,16,17,18,19,20,21,22,23,24,25,26]. The reaction has also been the focus of a large number of experimental measurements [27,28,29,30,31,32,33,34,35,36]. However, there still remains significant discrepancy between measured and computed values of its rate coefficients for temperatures below 200 K, which is the most important region for astrophysical and upper atmospheric applications.…”

Section: Introductionmentioning

confidence: 99%

Quantum dynamics of the O+OH→H+O2 reaction at low temperatures

Quéméner

Balakrishnan

Kendrick

2008

The Journal of Chemical Physics

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We report quantum dynamics calculations of the O + OH --> H + O(2) reaction on two different representations of the electronic ground state potential energy surface (PES) using a time-independent quantum formalism based on hyperspherical coordinates. Calculations show that several excited vibrational levels of the product O(2) molecule are populated in the reaction. Rate coefficients evaluated using both PESs were found to be very sensitive to the energy resolution of the reaction probability, especially at temperatures lower than 100 K. It is found that the rate coefficient remains largely constant in the temperature range of 10-39 K, in agreement with the conclusions of a recent experimental study [Carty et al., J. Phys. Chem. A 110, 3101 (2006)]. This is in contrast with the time-independent quantum calculations of Xu et al. [J. Chem. Phys. 127, 024304 (2007)] which, using the same PES, predicted nearly two orders of magnitude drop in the rate coefficient value from 39 to 10 K. Implications of our findings to oxygen chemistry in the interstellar medium are discussed.

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Section: Introductionmentioning

confidence: 99%

Quantum dynamics of the O+OH→H+O2 reaction at low temperatures

Quéméner

Balakrishnan

Kendrick

2008

The Journal of Chemical Physics

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“…However, the reaction rate constant of NO 2 with OH⅐ is approximately 3 orders of magnitude smaller than that of O with OH⅐. 43,45 This could explain why there were no measurable changes in the NO x concentrations in this study. Table 1 presents O 3 concentrations measured at 0-and 75-kW engine loads.…”

Section: Removal Of N-alkanes and 16 Pahsmentioning

confidence: 70%

Control of Diesel Gaseous and Particulate Emissions with a Tube-Type Wet Electrostatic Precipitator

2008

JAWMA

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In this study, experiments were performed with a benchscale tube-type wet electrostatic precipitator (wESPs) to investigate its effectiveness for the removal of mass-and number-based diesel particulate matter (DPM), hydrocarbons (HCs), carbon monoxide (CO), and oxides of nitrogen (NO x ) from diesel exhaust emissions. The concentration of ozone (O 3 ) present in the exhaust that underwent a nonthermal plasma treatment process inside the wESP was also measured. A nonroad diesel generator operating at varying load conditions was used as a stationary diesel emission source. The DPM mass analysis was conducted by means of isokinetic sampling and the DPM mass concentration was determined by a gravimetric method. An electrical low-pressure impactor (ELPI) was used to quantify the DPM number concentration. The HC compounds, n-alkanes, and polycyclic aromatic hydrocarbons (PAHs) were collected on a moisture-free quartz filter together with a PUF/XAD/PUF cartridge and extracted in dichloromethane with sonication. Gas chromatography (GC)/ mass spectroscopy (MS) was used to determine HC concentrations in the extracted solution. A calibrated gas combustion analyzer (Testo 350) and an O 3 analyzer were used for quantifying the inlet and outlet concentrations of CO and NO x (nitric oxide [NO] ϩ nitrogen dioxide [NO 2 ]), and O 3 in the diesel exhaust stream. The wESP was capable of removing approximately 67-86% of mass-and number-based DPM at a 100% exhaust volumetric flow rate generated from 0-to 75-kW engine loads. At 75-kW engine load, increasing gas residence time from approximately 0.1 to 0.4 sec led to a significant increase of DPM removal efficiency from approximately 67 to more than 90%. The removal of n-alkanes, 16 PAHs, and CO in the wESP ranged from 31 to 57% and 5 to 38%, respectively. The use of the wESP did not significantly affect NO x concentration in diesel exhaust. The O 3 concentration in diesel exhaust was measured to be less than 1 ppm. The main mechanisms responsible for the removal of these pollutants from diesel exhaust are discussed.

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“…This increase for OH + O (plus an increase in OH + HO 2 ) was also recommended to explain the new Aura HOx data [ Canty et al , 2006] and thus our optimization on the old data supports this result. Some new laboratory measurements also suggest a larger rate constant for OH + O at low temperatures [ Robertson and Smith , 2006].…”

Section: Multiple Solutionsmentioning

confidence: 99%

A system analysis approach for atmospheric observations and models: Mesospheric HO_x dilemma

et al. 2006

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[1] A systematic consistency analysis and optimization procedure is applied to models of representative ozone, OH, and HO 2 observations in the mesosphere and upper stratosphere. The approach considers both measurement and rate parameter uncertainties. The results show some data point inconsistencies and the inability of the accepted photochemical mechanism to predict observations without unfavored large alterations of many rate constants from their consensus values. Optimization results do favor larger rate constants for OH + O and photolytic ozone and OH production.Citation: Smith, G. P., M. Frenklach, R. Feeley, A. Packard, and P. Seiler (2006), A system analysis approach for atmospheric observations and models: Mesospheric HO x dilemma,

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Temperature Dependence of O + OH at 136−377 K Using Ozone Photolysis

Cited by 24 publications

References 26 publications

Quantum dynamics of the O+OH→H+O2 reaction at low temperatures

Quantum dynamics of the O+OH→H+O2 reaction at low temperatures

Control of Diesel Gaseous and Particulate Emissions with a Tube-Type Wet Electrostatic Precipitator

A system analysis approach for atmospheric observations and models: Mesospheric HO_x dilemma

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Temperature Dependence of O + OH at 136−377 K Using Ozone Photolysis

Cited by 24 publications

References 26 publications

Quantum dynamics of the O+OH→H+O2 reaction at low temperatures

Quantum dynamics of the O+OH→H+O2 reaction at low temperatures

Control of Diesel Gaseous and Particulate Emissions with a Tube-Type Wet Electrostatic Precipitator

A system analysis approach for atmospheric observations and models: Mesospheric HOx dilemma

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Product

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A system analysis approach for atmospheric observations and models: Mesospheric HO_x dilemma