Heat of formation of HO sub 2. A direct determination from guided ion beam studies of O sub 2 sup + ( sup 2 PI sub g ,v=0) + CH sub 4

Journal Article · Thu May 31 04:00:00 EDT 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100374a007· OSTI ID:6514445

Fisher, E R; Armentrout, P B ^[1]

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1. Univ. of Utah, Salt Lake City (USA)

The heat of formation of the hydroperoxyl radical, HO{sub 2}, and the ionization energy of methane, IE(CH{sub 4}), are measured directly, by using guided ion beam mass spectrometry to study the reaction of O{sub 2}{sup +}({sup 2}{Pi}{sub g},{nu}=0) + CH{sub 4}. The O{sub 2}{sup +} ions are produced in a flow tube source and are shown to be completely thermalized. The thermodynamic values derived are IE(CH{sub 4}) = 12.54 {plus minus} 0.07 eV, {Delta}{sub f}H{sub 298}(HO{sub 2}) = 3.8 {plus minus} 1.2 kcal/mol, D{sub 298}{degree}(H-OO) = 48.3 {plus minus} 1.2 kcal/mol, and D{sub 298}{degree}(H-OOH) = 88.4 {plus minus} 1.2 kcal/mol (where the uncertainties represent our 95% confidence limits). The present values are compared to prior experimental and theoretical values.

• OSTI ID: 6514445
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 94:11; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
54 ENVIRONMENTAL SCIENCES
540110*
ALKANES
ATMOSPHERIC CHEMISTRY
BEAMS
CHEMISTRY
DATA
DATA ANALYSIS
ENTHALPY
EXPERIMENTAL DATA
FORMATION HEAT
HYDROCARBONS
HYDROPEROXY RADICALS
INFORMATION
ION BEAMS
MEASURING INSTRUMENTS
MEASURING METHODS
METHANE
NUMERICAL DATA
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
RADICALS
REACTION HEAT
THERMODYNAMIC PROPERTIES