Rate constant measurements at constant temperature by the flash photolysis-resonance fluorescence technique. Recombination dissociation theory for nitrogen dioxide and nitrosyl chloride

1979 ◽  
Vol 83 (1) ◽  
pp. 10-17 ◽  
Author(s):  
J. V. Michael ◽  
J. H. Lee
Keyword(s):  
Nitrogen Dioxide ◽  
Constant Temperature ◽  
Rate Constant ◽  
Flash Photolysis ◽  
Fluorescence Technique ◽  
Resonance Fluorescence ◽  
Nitrosyl Chloride

Rate of the OH + C6H6 + He reaction in the fall-off range by discharge flow and OH resonance fluorescence

1991 ◽  
Vol 69 (7) ◽  
pp. 1057-1064 ◽  
Author(s):  
A. Goumri ◽  
J. F. Pauwels ◽  
P. Devolder
Keyword(s):  
Rate Constant ◽  
Room Temperature ◽  
Flash Photolysis ◽  
Tropospheric Chemistry ◽  
Resonance Fluorescence ◽  
Discharge Flow ◽  
Gas Phase Kinetics ◽  
Radical Adduct ◽  
Fluorescence Reaction ◽  
Two Temperatures

The rate constant k1 of the reaction[Formula: see text]has been investigated by discharge flow resonance fluorescence of OH in the fall-off pressure range. From systematic measurements at five pressures between 0.5 and 9.5 torr, the Troe parameters k0 and k∞ (with Fc = 0.6) have been derived at two temperatures: room temperature and 353 K. For room temperature, (297 ± 3) K, these parameters are k0 = (1.7 ± 0.5) × 10−29 cm6 molecule−2 s−1, k∞, = (10 ± 2) × 10−13 cm3 molecule−1 s−1. Our experimental results are consistent with addition as the dominant path, in agreement with flash photolysis investigations and with the existence of a fast reaction with NO2 of the (OH—benzene) radical adduct. A numerical simulation shows that this latter reaction should have a rate constant of (4 ± 2) × 10−11 cm3 molecule−1 s−1 at 353 K. Key words: gas phase kinetics, discharge flow, resonance fluorescence, reaction of OH with benzene, tropospheric chemistry.

The production of NO 3 in the photolysis of nitrogen dioxide and of nitric acid vapour under isothermal conditions

1963 ◽  
Vol 273 (1353) ◽  
pp. 165-179 ◽  
Keyword(s):  
Nitric Acid ◽  
Nitrogen Dioxide ◽  
Rate Constant ◽  
Room Temperature ◽  
Flash Photolysis ◽  
Quantitative Agreement ◽  
Kinetic Measurements ◽  
Isothermal Conditions

The NO 3 radical has been observed as a result of the flash photolysis of nitrogen dioxide under isothermal conditions (room temperature). Its concentration has been m easured together with the rate constant for the reaction NO + NO 3 = 2NO 2 . This has been found to be in quantitative agreement with previous kinetic measurements on the straight photolysis of nitrogen dioxide. The flash photolysis of nitric acid vapour under isothermal conditions also yielded NO 3 as an intermediate. The basis of a mechanism is reported. The NO 3 results from the reaction OH + HNO 3 = H 2 O + NO 3 , for which the rate constant has been measured.

Mechanistic studies of aromatic ketone-sensitized photoreduction of bis(acetylacetonato)copper(II)

1983 ◽  
Vol 61 (5) ◽  
pp. 801-808 ◽  
Author(s):  
Yuan L. Chow ◽  
Gonzalo E. Buono-Core ◽  
Bronislaw Marciniak ◽  
Carol Beddard
Keyword(s):  
Rate Constant ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Decay Rates ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Aromatic Ketone ◽  
Quantum Yields ◽  
Triplet States ◽  
Quenching Rate ◽  
Triplet Energy

Bis(acetylacetonato)copper(II), Cu(acac)2, quenches triplet excited states of ketones and polynuclear aromatic hydrocarbons efficiently, but only aromatic ketones with high triplet energy successfully sensitize photoreduction of Cu(acac)2 in alcohols under nitrogen to give derivatives of aeetylacetonatocopper(I), Cu(acac). For the triplet state benzophenone-sensitized photoreduction of Cu(acac)2, the quantum yields of photoreduction (ΦC) and those of benzophenone disappearance (ΦB) were determined in methanol with various concentrations of Cu(acac)2. The values of the quenching rate constant, kq, determined from these two types of monitors on the basis of the proposed mechanism were in good agreement (6.89 ~ 7.35 × 109 M−1 s−1). This value was higher, by a factor of about two, than that obtained from the monitor of the benzophenone triplet decay rates generated by flash photolysis in the presence of Cu(acac)2. The quenching rate constants of various aromatic ketone and hydrocarbon triplet states by Cu(acac)2 were determined by flash photolysis to be in the order of the diffusion rate constant and the quantum yields of these photoreductions were found to be far from unity. Paramagnetic quenching, with contributions of electron exchange and charge transfer, was proposed as a possible quenching mechanism. For a series of aromatic ketone sensitizers with higher triplet energy, this mechanism was used to rationalize the observed high quenching rate constants in contrast to the low quantum yields of photoreduction.

The Reaction of S(3P) Atoms with Molecular Oxygen

1971 ◽  
Vol 49 (10) ◽  
pp. 1659-1664 ◽  
Author(s):  
R. W. Fair ◽  
A. Van Roodselaar ◽  
O. P. Strausz
Keyword(s):  
Molecular Oxygen ◽  
Rate Constant ◽  
Ground State ◽  
Vacuum Ultraviolet ◽  
Flash Photolysis ◽  
Ultraviolet Region ◽  
Kinetic Spectroscopy ◽  
Vacuum Ultraviolet Region

The rate constant of the reaction of ground state S(3P) atoms with molecular oxygen, S(3P) + O2(X3Σg−) → SO(X3Σ−) + O(3P), has been determined as (1.7 ± 0.2) × 1012 cm3 mol−s− at 298 °K by means of kinetic spectroscopy in the vacuum ultraviolet region. The source of S(3P) atoms was the isothermal flash photolysis of COS in the presence of Ar or CO2.

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