Formation, Lifetime, and Decay of OH Radicals in Discharge-Flow Systems

Kaufman, F.; Greco, Frank P. Del

doi:10.1063/1.1732163

Cited by 32 publications

(5 citation statements)

References 8 publications

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“…While the percent exothermicity which is channeled into vibrational modes of OH as determined by each of these investigations is somewhat different, all report that at least 25% of the 28-kcal/mol exothermicity is used to populate OH = 1, 2, and 3. This value is in substantial disagreement with earlier work by Kaufman and Del Greco,4 who reported less than 2% (the limit of their detectivity) excitation of OH(u = 1) in a flow discharge system. Since many workers5'7 have used the + N02 reaction as a source of OH for subsequent reaction studies, it is important to quantify the presence of vibrationally excited species prior to subsequent reactions.…”

Section: Introductioncontrasting

confidence: 99%

Vibrationally excited hydroxyl in the products of the atomic hydrogen + nitrogen dioxide reaction

Smith¹,

Fisher²

1978

J. Phys. Chem.

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The presence of vibrationally excited OH in the products of the H + N02 reaction has been confirmed by detailed spectroscopic analysis of the IR emission. The observations were carried out in a fast flow discharge reactor at room temperature and at total pressures near 1 Torr. Although diffusion limited mixing was evident in our system, the presence of vibrationally excited OH restricts the range over which the H + N02 reaction can be used as a source of ground state OH for subsequent reaction studies.

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Section: Introductioncontrasting

confidence: 99%

Vibrationally excited hydroxyl in the products of the atomic hydrogen + nitrogen dioxide reaction

Smith¹,

Fisher²

1978

J. Phys. Chem.

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“…(Again, this percentage was obtained from the ratio of the oxygen concentration without (T6.12) to the total oxygen concentration at the end of the pulse with (T6.1) and (T6.15).) Pathway ( 1) is supported by the work of Kaufman and Del Greco [31] where the gas phase discharge of water vapour is studied and the same reaction for the oxygen formation was reported. Pathway ( 2) is supported by the work of Sahni [32] where one of the possible pathways for the oxygen formation is the same as presented here in pathway 2.…”

Section: Recombination Regionmentioning

confidence: 89%

Primary chemical reactions in pulsed electrical discharge channels in water

Međedović¹,

Locke²

2007

J. Phys. D: Appl. Phys.

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A mathematical model for the primary chemical processes occurring in 1 J/pulse electrical discharges in water has been developed. The discharge channel is divided into two zones: the core and the recombination region. The core is a very narrow (ca 10 µm) part of the channel where high temperature initiation reactions take place and where the majority of molecular hydrogen and 47% of the molecular oxygen are formed. The recombination region is a 200 µm radius zone where additional reactions such as hydrogen peroxide formation take place. The temperature in the core ranged from 5000 K at the centre to 2000 K at the boundary and the pressure, the only adjustable parameter in the system, was found to be 14 atm. The model describes for the first time how molecular oxygen is formed in an underwater discharge and it is also able to describe the experimentally observed stoichiometry of H2, O2 and H2O2 formation. The concentration and temperature profiles inside the discharge channel as well as a general scheme for the water dissociation and molecular species formation are also reported.

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“…The application of the discharge flow technique to kinetic measurements of OH reactions was pioneered by Kaufman and Del Greco [10][11][12]. They showed that the reaction H+NO2 ~ OH+NO is a clean source of OH radicals for kinetic measurements, whereas OH from an electric discharge in water gives erroneous kinetic results because of secondary production of OH downstream from the discharge.…”

Section: A Direct Techniquesmentioning

confidence: 99%

“…The following approximate detection limits for OH of the various techniques, in mol/cm 3, were taken from Atkinson's review [4]: RA, 10-1°-10 -13, the sensitivity can be increased by multiple passes; RF and LIF, 10-12-10-15; ESR, 10-11-10-13; MS, 10-11-10-12; LMR, 10 -13- [10][11][12][13][14][15].…”

Section: A Direct Techniquesmentioning

confidence: 99%