Measurement of the rate of hydrogen atom abstraction from methane and ethane by muonium

Reaction rates for the gas-phase reactions Mu+ CH₄ → MuH + CH₃ and Mu + C₂H₆ → MuH + C₂H₅ have been measured using μSR over the temperature ranges 626-821 K and 511-729 K respectively. The usual Arrhenius plots for each data set are linear. The measured parameters A are 5.7 [+4.8 superscript and -2.5 subscript] x 10⁻⁸ and 1.0 [+0.7 superscript and -0.4 subscript] x 10⁻⁹ cm³ molecule⁻¹ s⁻¹, and the parameters E [α subscript], 24.66 [+0.88 superscript and -0.82 subscript] and 15.35 [+0.65 superscript and +0.59 subscript] kcal/mol respectively. The E [α subscript] values are 11.5 and 5.5 kcal/mol higher than for the corresponding H atom reactions. The very large increases in E [α subscript] seem to indicate drastic differences between the Mu and H variants of the title reactions, in location of the transition states on the potential energy surfaces. Also, for the Mu variants, the reaction rates seem to be reduced less for vibrationally excited states of CH₄ and C₂H₆than for the ground states than is the case for the corresponding H atom reactions, an effect which contributes to the large increase in activation energy for Mu.

Name thesis:degree_name

Master of Science - MSc

Level thesis:degree_level

master's

Discipline thesis:degree_discipline

Chemistry

Grantor dc:publisher

University of British Columbia

Year dc:date

1993

Author dc:creator

• Snooks, Rodney J.

Statement dc:rights

• For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.

Language dc:language

eng

Handle dc:identifier

http://hdl.handle.net/2429/1134

OAI identifier oai:identifier

oai:circle.library.ubc.ca:2429/1134