Temperature and pressure dependence of the reaction CH + H sub 2

Journal Article · Thu Mar 21 04:00:00 EST 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100159a050· OSTI ID:5542863

Becker, K H; Kurtenbach, R; Wiesen, P ^[1]

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1. Wuppertal Univ. Gesamthochschule (West Germany)

The reaction CH(X{sup 2}{Pi}) + H{sub 2} was studied as a function of temperature in the range 200-400 K at 4 Torr total pressure and as a function of total pressure in the range 2-592 Torr at 298 K. CH radicals were generated by excimer laser photolysis of CHClBr{sub 2}/Ar mixtures and were detected by laser-induced fluorescence. The reaction proceeds along two pathways: Above 300 K, production of CH{sub 2} + H dominates with an activation energy of 13.82 {plus minus} 4.19 kJ{center dot}mol{sup {minus}1}, whereas below 300 K, the rate constants exhibit a negative temperature dependence with an activation energy of -6.12 {plus minus} 1.93 kJ{center dot}mol{sup {minus}1} consistent with an adduct formation followed by collisional stabilization. The limiting rate constants k{sub 0} and k{sub {infinity}} and the broadening factor F{sub c} were determined from the pressure dependence. A transition-state-theory model was applied to analyze the experimental results.

• OSTI ID: 5542863
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:6; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ACTIVATION ENERGY
ALKYL RADICALS
ARGON
ARRHENIUS EQUATION
CHEMICAL REACTIONS
DATA
DECOMPOSITION
DISPERSIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
EMISSION SPECTROSCOPY
ENERGY
EQUATIONS
EXPERIMENTAL DATA
FLUIDS
FLUORESCENCE SPECTROSCOPY
GASES
HYDROGEN
HYDROGENATION
INFORMATION
LASER RADIATION
LOW PRESSURE
MATHEMATICAL MODELS
MIXTURES
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PRESSURE DEPENDENCE
RADIATIONS
RADICALS
RARE GASES
SPECTROSCOPY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
THEORETICAL DATA