Rate constants for the reactions H+O sub 2 r arrow OH+O and D+O sub 2 r arrow OD+O over the temperature range 1085--2278 K by the laser photolysis--shock tube technique

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.461483· OSTI ID:5556156

Shin, K S; Michael, J V ^[1]

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1. Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (USA)

Rate constants for the reactions (1) H+O{sub 2}{r arrow}OH+O and (2) D+O{sub 2}{r arrow}OD+O have been measured over the temperature ranges 1103--2055 K and 1085--2278 K, respectively. The experimental method that has been used is the laser-photolysis--shock-tube technique. This technique utilizes atomic resonance absorption spectrophotometry (ARAS) to monitor H- or D-atom depletion in the presence of a large excess of reactant, O{sub 2}. The results can be well represented by the Arrhenius expressions {ital k}{sub 1}({ital T})=(1.15{plus minus}0.16){times}10{sup {minus}10} exp({minus}6917{plus minus}193 K/{ital T}) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}, and {ital k}{sub 2}({ital T})=(1.09{plus minus}0.20){times}10{sup {minus}10} exp({minus}6937{plus minus}247 K/{ital T}) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. Over the experimental temperature range, the present results show that the isotope effect is unity within experimental uncertainty. The Arrhenius equations, {ital k}{sub {minus}1}({ital T})=(8.75{plus minus}1.24) {times}10{sup {minus}12} exp(1121{plus minus}193 K/{ital T}) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1} and {ital k}{sub {minus}2} ({ital T})=(9.73{plus minus}1.79){times}10{sup {minus}12} exp(526{plus minus}247 K/{ital T}) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}, for the rate constants of the reverse reactions were calculated from the experimentally measured forward rate constants and expressions for the equilibrium constants that have been derived from the JANAF thermochemical database. The theoretical implications of the present results are also discussed.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5556156
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 95:1; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400800 -- Combustion
Pyrolysis
& High-Temperature Chemistry
ARRHENIUS EQUATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMBUSTION
DECOMPOSITION
DEUTERIUM
ELECTROMAGNETIC RADIATION
ELEMENTS
EQUATIONS
HYDROGEN
HYDROGEN ISOTOPES
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LASER RADIATION
LIGHT NUCLEI
NONMETALS
NUCLEI
ODD-ODD NUCLEI
OXIDATION
OXYGEN
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADIATIONS
REACTION KINETICS
SHOCK TUBES
STABLE ISOTOPES
THERMOCHEMICAL PROCESSES
VERY HIGH TEMPERATURE