Temperature dependence of the O+I({sup 2}P{sub 1/2})->O+I({sup 2}P{sub 3/2}) quenching rate constant

Journal Article · Fri May 01 04:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3125455· OSTI ID:21356155

Mikheyev, Pavel A; Postell, David J; Heaven, Michael C ^[1]

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1. Department of Chemistry, Emory University, Atlanta, Georgia 30322 (United States)

The rate constant for quenching of I({sup 2}P{sub 1/2}) by O({sup 3}P) has been measured for the temperature range 295-360 K. Pulsed laser photolysis of mixtures N{sub 2}O and I{sub 2} was used to examine the kinetics. O({sup 3}P) atoms were produced by the photoinitiated reaction sequences N{sub 2}O+hnu->O({sup 1}D)+N{sub 2} and O({sup 1}D)+M->O({sup 3}P)+M, while singlet oxygen was generated by the secondary reaction O({sup 1}D)+N{sub 2}O->O{sub 2}(a {sup 1}DELTA)+N{sub 2}. Iodine atoms were produced by I{sub 2} photodissociation and from the secondary reactions of I{sub 2} with O({sup 3}P) atoms. Subsequent excitation of I by O{sub 2}(a {sup 1}DELTA) led to I({sup 2}P{sub 1/2}) formation, with I({sup 2}P{sub 1/2}) concentrations monitored using time-resolved 1315 nm emission. The rate constant of the quenching process was determined by fitting a kinetic model to the observed emission traces. Special attention was given to the gas flow conditions. A modest temperature dependence of the quenching rate constant was found, and this was well represented by the equation k=(6.5+-1)x10{sup -12}(T/300){sup 1.76} cm{sup 3} s{sup -1}. The room temperature rate constant differs from previous experimental determinations but agrees well with the value determined by modeling of the data from discharge driven oxygen-iodine lasers.

• OSTI ID: 21356155
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 105; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DISSOCIATION
ELEMENTS
FLUID FLOW
GAS FLOW
GAS LASERS
HALOGENS
IODINE
IODINE LASERS
KINETICS
LASERS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NITROUS OXIDE
NONMETALS
NUCLEAR REACTIONS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOLYSIS
QUENCHING
REACTION KINETICS
RESOLUTION
SECONDARY REACTIONS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TIME RESOLUTION
TIMING PROPERTIES